Methods and compositions for improving cognitive function

Title: Methods and compositions for improving cognitive function.Abstract: This invention relates to treating age-related cognitive impairment. This invention in particular relates to the use of inhibitors of synaptic vesicle protein 2A (SV2A), such as levetiracetam, seletracetam, and brivaracetam, in improving cognitive function in subjects that exhibit age-related cognitive impairment or are at risk thereof, including, without limitation, subjects having or at risk for Mild Cognitive Impairment (MCI), Age-related Cognitive Decline (ARCD) or Age-Associated Memory Impairment (AAMI). ...

This invention relates to treating age-related cognitive impairment. This invention in particular relates to the use of inhibitors of synaptic vesicle protein 2A (SV2A), such as levetiracetam, seletracetam, and brivaracetam, in improving cognitive function in subjects that exhibit age-related cognitive impairment or are at risk thereof, including, without limitation, subjects having or at risk for Mild Cognitive Impairment (MCI), Age-related Cognitive Decline (ARCD) or Age-Associated Memory Impairment (AAMI).

This application claims priority and benefit from U.S. Provisional Patent Applications 61/105,847 (filed Oct. 16, 2008), 61/152,631 (filed Feb. 13, 2009) and 61/175,536 (filed May 5, 2009). The contents and disclosures of each of these prior provisional applications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to methods and compositions for treating age-related cognitive impairment. In particular, it relates to the use of inhibitors of synaptic vesicle glycoprotein 2A (SV2A) in treating age-related cognitive impairment in a subject in need or at risk thereof, including, without limitation, subjects having or at risk for Mild Cognitive Impairment (MCI), Age-Associated Memory Impairment (AAMI) or Age Related Cognitive Decline (ARCD).

BACKGROUND OF THE INVENTION

Cognitive ability may decline as a normal consequence of aging. Moreover, a significant population of elderly adults experiences a decline in cognitive ability that exceeds what is typical in normal aging.

Such age-related loss of cognitive function is characterized clinically by progressive loss of memory, cognition, reasoning, and judgment. Mild Cognitive Impairment (MCI), Age-Associated Memory Impairment (AAMI), Age-Related Cognitive Decline (ARCD) or similar clinical groupings are among those related to such age-related loss of cognitive function. According to some estimates, there are more than 16 million people with AAMI in the U.S. alone (Barker et al., 1995), and MCI is estimated to affect 5.5-7 million in the U.S. over the age of 65 (Plassman et al., 2008) There is, therefore, a need for effective treatment for age-related cognitive impairment and to improve cognitive function in patients diagnosed with MCI, AAMI, ARCD and similar age-associated cognitive impairments or at risk of developing them.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there is provided a method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of a synaptic vesicle protein 2A (SV2A) inhibitor or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, the SV2A inhibitor is selected from the group of SV2A inhibitors referred to in International Patent Application WO 2001/062726, International Patent Application WO 2002/094787, International Patent Application WO 2004/087658, U.S. Pat. No. 7,244,747, International Patent Application WO 2007/065595, US Patent Application 2008/0081832, International Patent Application WO 2006/128692, International Patent Application WO 2006/128693, UK Patent No. 1,039,113, and UK Patent No. 1,309,692. In certain embodiments of the invention, the SV2A inhibitor is selected from the group of levetiracetam, brivaracetam, and seletracetam or pharmaceutically acceptable salts thereof. In certain embodiments of the invention, the SV2A inhibitor or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a dose of about 0.1 to 5 mg/kg, or about 1 to 2 mg/kg, or about 0.1 to 0.2 mg/kg, or about 0.01 to 2.5 mg/kg, or about 0.1-2.5 mg/kg, or about 0.4-2.5 mg/kg, or about 0.6-1.8 mg/kg, or about 0.04-2.5 mg/kg or about 0.06-1.8 mg/kg.

In accordance with a second aspect of the present invention, there is provided a method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject an SV2A inhibitor or a pharmaceutically acceptable salt thereof in combination with valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, valproate is administered at a daily dose such that the subject maintains a blood total valproate level of 0.5 to 5 μg/ml plasma, and the SV2A inhibitor is administered at a daily dose of is 0.01 to 1 mg/kg. In certain embodiments of the invention, valproate is administered at a daily dose such that the subject maintains a blood total valproate level of 0.5 to 5 μg/ml plasma, and the SV2A inhibitor is administered at a daily dose of 0.001 to 1 mg/kg. In certain embodiments of the invention, the SV2A inhibitor is selected from the group of SV2A inhibitors referred to in International Patent Application WO 2001/062726, International Patent Application WO 2002/094787, International Patent Application WO 2004/087658, U.S. Pat. No. 7,244,747, International Patent Application WO 2007/065595, US Patent Application 2008/0081832, International Patent Application WO 2006/128692, International Patent Application WO 2006/128693, UK Patent No. 1,039,113, and UK Patent No. 1,309,692. In certain embodiments of the invention, the SV2A inhibitor is selected from the group of levetiracetam, brivaracetam, and seletracetam or pharmaceutically acceptable salts thereof. In certain embodiments of the invention, the SV2A inhibitor or a pharmaceutically acceptable salt thereof and valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof are administered simultaneously, sequentially, or as a single formulation.

In accordance with a third aspect of the present invention, there is provided a pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, the SV2A inhibitor is present in an amount of 5-140 mg. In other embodiments of the invention, the SV2A inhibitor is present in an amount of 0.7-180 mg.

In accordance with a fourth aspect of the present invention, there is provided a pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof and valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, the SV2A inhibitor is present in an amount of 3-50 mg. In other embodiments of the invention, the SV2A inhibitor is present in an amount of 0.07-50 mg.

In accordance with a fifth aspect of the present invention, there is provided a method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of levetiracetam or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 1-2 mg/kg. In certain embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 70-150 mg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.1-2.5 mg/kg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 7-180 mg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.4-2.5 mg/kg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 25-180 mg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.6-1.8 mg/kg. In some embodiments of the invention, levetiracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 40-130 mg.

In accordance with a sixth aspect of the present invention, there is provided a method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of brivaracetam or a pharmaceutically acceptable salt thereof. In certain embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.1-0.2 mg/kg. In certain embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 7-15 mg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.01-2.5 mg/kg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.7-180 mg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.04-2.5 mg/kg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 2.5-180 mg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 0.06-1.8 mg/kg. In some embodiments of the invention, brivaracetam or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of about 4-130 mg.

In accordance with a seventh aspect of the present invention, there is provided a method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of seletracetam or a pharmaceutically acceptable salt thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts increased mRNA expression of the gene encoding SV2A in the dentate gyms of the hippocampus of aged-impaired rats (AI) as compared to young rats (Y) and aged-unimpaired rats (AU). Normalized Affymetrix GeneChip probe set signal values (Y-axis), as a measure of mRNA expression, are plotted against learning indices of different rats, as a measure of cognitive impairment.

FIG. 2 depicts the effects of administering levetiracetam on the spatial memory retention of six aged-impaired rats (AI) in a Morris Water Maze (MWM) test. Three treatment conditions were employed: vehicle control, levetiracetam (5 mg/kg/day) and levetiracetam (10 mg/kg/day). The AI rats were trained for two consecutive days, with a one-time treatment prior to the training trials per day. 24 hours later, the AI rats were tested. The time the AI rats, 24 hours after treatment with the different conditions and two days of training, spent swimming in the target quadrant or the target annulus in a memory retention trial is used as a measure of spatial memory retention. The target quadrant refers to the quadrant of the maze (which is a circular pool) where the escape platform is placed during the training trials. The target annulus refers to the exact location of the escape platform during the training trials.

FIG. 3 depicts the effects of administering levetiracetam on the spatial memory retention of ten aged-impaired rats (AI) in an eight-arm Radial Arm Maze (RAM) test. Six treatment conditions were employed: vehicle control, levetiracetam (1.25 mg/kg/day), levetiracetam (2.5 mg/kg/day), levetiracetam (5 mg/kg/day), levetiracetam (10 mg/kg/day) and levetiracetam (20 mg/kg/day). In the RAM task used, there was a one-hour delay between presentation of a subset of arms (5 arms available and 3 arms blocked) and completion of the eight-arm win-shift task (eight arms available). Rats were pre-treated 30-40 minutes before daily trials with a one-time drug/control treatment. The number of errors made by the rats after the delay was used as a measure of spatial memory retention. Errors were defined as instances when rats entered an arm from which food had already been retrieved in the pre-delay component of the trial or when rats re-visited an arm in the post-delay session that had already been visited. Paired t-tests were used to compare the number of errors between different doses of levetiracetam and vehicle control.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise defined herein, scientific and technical terms used in this application shall have the meanings that are commonly understood by those of ordinary skill in the art. Generally, nomenclature used in connection with, and techniques of, cell and tissue culture, molecular biology, cell and cancer biology, neurobiology, neurochemistry, virology, immunology, microbiology, pharmacology, genetics and protein and nucleic acid chemistry, described herein, are those well known and commonly used in the art.

Chemistry terms used herein are used according to conventional usage in the art, as exemplified by “The McGraw-Hill Dictionary of Chemical Terms”, Parker S., Ed., McGraw-Hill, San Francisco, C.A. (1985).

All of the above, and any other publications, patents and published patent applications referred to in this application are specifically incorporated by reference herein. In case of conflict, the present specification, including its specific definitions, will control.

Throughout this specification, the word “comprise” or variations such as “comprises” or “comprising” will be understood to imply the inclusion of a stated integer (or components) or group of integers (or components), but not the exclusion of any other integer (or components) or group of integers (or components).

The singular forms “a,” “an,” and “the” include the plurals unless the context clearly dictates otherwise.

The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.

The term “agent” is used herein to denote a chemical compound (such as an organic or inorganic compound, a mixture of chemical compounds), a biological macromolecule (such as a nucleic acid, an antibody, including parts thereof as well as humanized, chimeric and human antibodies and monoclonal antibodies, a protein or portion thereof, e.g., a peptide, a lipid, a carbohydrate), or an extract made from biological materials such as bacteria, plants, fungi, or animal (particularly mammalian) cells or tissues. Agents include, for example, agents which are known with respect to structure, and those which are not known with respect to structure. The SV2A inhibitory activity of such agents may render them suitable as “therapeutic agents” in the methods and compositions of this invention.

A “patient”, “subject”, or “individual” are used interchangeably and refer to either a human or a non-human animal. These terms include mammals, such as humans, primates, livestock animals (including bovines, porcines, etc.), companion animals (e.g., canines, felines, etc.) and rodents (e.g., mice and rats).

In animal model systems, cognitive function may be measured in various conventional ways known in the art, including using a Morris Water Maze (MWM), Barnes circular maze, elevated radial arm maze, T maze or any other mazes in which the animals use spatial information. Other tests known in the art may also be used to assess cognitive function, such as novel object recognition and odor recognition tasks.

Cognitive function may also be measured using imaging techniques such as Positron Emission Tomography (PET), functional magnetic resonance imaging (fMRI), Single Photon Emission Computed Tomography (SPECT), or any other imaging technique that allows one to measure brain function. In animals, cognitive function may also be measured with electrophysiological techniques.

“Age-related cognitive impairment” or “cognitive impairment” refers to cognitive function in aged subjects that is not as robust as that expected in an age-matched normal subject (i.e. subjects with mean scores for a given age in a cognitive test) or as that expected in young adult subjects. In some cases, cognitive function is reduced by about 5%, about 10%, about 30%, or more, compared to cognitive function expected in an age-matched normal subject. In some cases, cognitive function is as expected in an age-matched normal subject, but reduced by about 5%, about 10%, about 30%, about 50% or more, compared to cognitive function expected in a young adult subject. Age-related impaired cognitive function may be associated with Mild Cognitive Impairment (MCI), Age-Associated Memory Impairment (AAMI), and Age-related Cognitive Decline (ARCD).

“Promoting” cognitive function refers to affecting age-related impaired cognitive function so that it more closely resembles the function of an aged-matched normal, unimpaired subject, or the function of a young adult subject. Cognitive function may be promoted to any detectable degree, but in humans preferably is promoted sufficiently to allow an impaired subject to carry out daily activities of normal life at the same level of proficiency as an aged-matched normal, unimpaired subject or as a young adult subject.

“Preserving” cognitive function refers to affecting normal or impaired cognitive function such that it does not decline or does not fall below that observed in the subject upon first presentation or diagnosis, or delays such decline.

“Age-Associate Memory Impairment (AAMI)” refers to a decline in memory due to aging. A patient may be considered to have AAMI if he or she is at least 50 years old and meets all of the following criteria: a) The patient has noticed a decline in memory performance, b) The patient performs worse on a standard test of memory compared to young adults, c) All other obvious causes of memory decline, except normal aging, have been ruled out (in other words, the memory decline cannot be attributed to other causes such as a recent heart attack or head injury, depression, adverse reactions to medication, Alzheimer's disease, etc.).

“Age-Related Cognitive Decline (ARCD)” refers to declines in memory and cognitive abilities that are a normal consequence of aging in humans (e.g., Craik & Salthouse, 1992). This is also true in virtually all mammalian species. Age-Associated Memory Impairment refers to older persons with objective memory declines relative to their younger years, but cognitive functioning that is normal relative to their age peers (Crook et al., 1986). Age-Consistent Memory Decline, is a less pejorative label which emphasizes that these are normal developmental changes (Crook, 1993; Larrabee, 1996), are not pathophysiological (Smith et al., 1991), and rarely progress to overt dementia (Youngjohn & Crook, 1993). The DSM-IV (1994) has codified the diagnostic classification of ARCD.

“Treating” a condition or patient refers to taking steps to obtain beneficial or desired results, including clinical results. Beneficial or desired clinical results include, but are not limited to, alleviation or amelioration of one or more symptoms associated with age-related cognitive impairment, delay or slowing of that impairment, amelioration, palliation or stabilization of that impairment, and other beneficial results, such as improvement of cognitive function or a reduced rate of decline of cognitive function in subjects with age-related cognitive impairment or at risk thereof.

“Administering” or “administration of” a substance, a compound or an agent to a subject can be carried out using one of a variety of methods known to those skilled in the art. For example, a compound or an agent can be administered, intravenously, arterially, intradermally, intramuscularly, intraperitonealy, intravenously, subcutaneously, ocularly, sublingually, orally (by ingestion), intranasally (by inhalation), intraspinally, intracerebrally, and transdermally (by absorbtion, e.g., through a skin duct). A compound or agent can also appropriately be introduced by rechargable or biodegradable polymeric devices or other devices, e.g., patches and pumps, or formulations, which provide for the extended, slow or controlled release of the compound or agent. Administering can also be performed, for example, once, a plurality of times, and/or over one or more extended periods. In some aspects, the administration includes both direct administration, including self-administration, and indirect administration, including the act of prescribing a drug. For example, as used herein, a physician who instructs a patient to self-administer a drug, or to have the drug administered by another and/or who provides a patient with a prescription for a drug is administering the drug to the patient.

Appropriate methods of administering a substance, a compound or an agent to a subject will also depend, for example, on the age of the subject, whether the subject is active or inactive at the time of administering, whether the subject is cognitively impaired at the time of administering, the extent of the impairment, and the chemical and biological properties of the compound or agent (e.g. solubility, digestibility, bioavailability, stability and toxicity). Preferably, a compound or an agent is administered orally, e.g., to a subject by ingestion. In some embodiments, the orally administered compound or agent is in an extended release or slow release formulation, or administered using a device for such slow or extended release.

A “therapeutically effective amount” of a drug or agent is an amount of a drug or an agent that, when administered to a subject will have the intended therapeutic effect, e.g. improving cognitive function in a subject, e.g., a patient with age-related cognitive impairment or a patient at risk thereof. The full therapeutic effect does not necessarily occur by administration of one dose, and may occur only after administration of a series of doses. Thus, a therapeutically effective amount may be administered in one or more administrations. The precise effective amount needed for a subject will depend upon, for example, the subject's size, health and age, the nature and extent of the cognitive impairment, and the therapeutics or combination of therapeutics selected for administration, and the mode of administration. The skilled worker can readily determine the effective amount for a given situation by routine experimentation.

“Synaptic vesicle protein-2 (SV2)” is a family of synaptic vesicle proteins, which consists of three members, designated SV2A, SV2B, and SV2C. SV2A is the most widely distributed family member, being expressed ubiquitously in the brain. The proteins are integral membrane proteins and have a low-level homology (20-30%) to the twelve transmembrane family of bacterial and fungal transporter proteins that transport sugar, citrate, and xenobiotics (Bajjalieh et al., Science. 257: 1271-1273. (1992)). SV2 family proteins are present in the brain and endocrine cells, and further are present in all synaptic and endocrine vesicles. SV2 proteins are reported to play a role in normal synaptic function, and functions in a maturation step of primed vesicles that converts the vesicles into a Ca(2+)- and synaptotagmin-responsive state (Sudhof et al., 2009). Functionally, SV2 proteins are reported to enhance synaptic currents and increase the probability of transmitter release by maintaining the size of the readily releasable pool of vesicles (Custer et al., 2006).

“Inhibitor of SV2A” refers to any agent, substance or compound that binds to SV2A and reduces synaptic function by reducing pre-synaptic vesicle release (See, e.g., Noyer et al. 1995; Fuks et al. 2003; Lynch et al. 2004; Gillard et al. 2006; Custer et al., 2006; Smedt et al., 2007; Yang et al., 2007; and Example 8 of WO 2001/62726, all of which are specifically incorporated herein by reference.) A substance, or a compound or an agent is an inhibitor of SV2A even if it does not itself bind to SV2A, as long as it causes, or affects the ability of, another compound or agent to bind SV2A or reduce synaptic function by reducing pre-synaptic vesicle release Inhibitors of SV2A, as used herein, include pharmaceutically acceptable salts and solvates of the inhibitors thereof.

Among the SV2A inhibitors useful for the methods and compositions of this invention, are those compounds or agents referred to in: i) International Patent Application WO 2001/062726; ii) International Patent Application WO 2002/094787; iii) International Patent Application WO 2004/087658; iv) U.S. Pat. No. 7,244,747; and v) International Patent Application WO 2007/065595. Applicants also refer to methods of preparing these compounds found in the documents cited above. Other synthetic methods may also be used. These methods are well known to those skilled in the art.

i) International Patent Application WO 2001/062726:

A compound having the formula I or a pharmaceutically acceptable salt thereof,

with the provisos that at least one of as R2, R3, R2a, R3a and R4a is other than hydrogen; and that when the compound is a mixture of all possible isomers, X is —CONR5R6, A2 is oxygen and R1 is hydrogen, methyl, ethyl or propyl then substitution on the pyrollidine ring is other than mono-, di-, or tri-methyl or mono-ethyl; and that when R1, R2, R4, R2a, R3a and R4a are each hydrogen, A2 is oxygen and X is CONR5R6 then R3 is different from carboxy, ester, amido, substituted oxo-pyrrolidine, hydroxy, oxy derivative, amino, amino derivatives, methyl, naphthyl, phenyl optionally substituted by oxy derivatives or in the para position by an halogen atom.

In the definitions set forth below, unless otherwise stated, R11 and R12 are the same or different and each is independently amido, alkyl, alkenyl, alkynyl, acyl, ester, ether, aryl, aralkyl, heterocycle or an oxy derivative, thio derivative, acyl derivative, amino derivative, sulfonyl derivative, or sulfinyl derivative, each optionally substituted with any suitable group, including, but not limited to, one or more moieties selected from lower alkyl or other groups as described below as substituents for alkyl.

The term “thio derivative” as used herein, is defined as including-S—R11 groups wherein R11 is as defined above except for “thio derivative”. Non-limiting examples are alkylthio, alkenylthio, alkynylthio and arylthio.

The term “amino derivative” as used herein, is defined as including-NHR11 or —NR11R12 groups wherein R11 and R12 are as defined above. Non-limiting examples are mono- or di-alkyl-, alkenyl-, alkynyl- and arylamino or mixed amino.

The term “acyl derivative” as used herein, represents a radical derived from carboxylic acid and thus is defined as including groups of the formula R11—CO—, wherein R11 is as defined above and may also be hydrogen. Non-limiting examples are formyl, acetyl, propionyl, isobutyryl, valeryl, lauroyl, heptanedioyl, cyclohexanecarbonyl, crotonoyl, fumaroyl, acryloyl, benzoyl, naphthoyl, furoyl, nicotinoyl, 4-carboxybutanoyl, oxalyl, ethoxalyl, cysteinyl, oxamoyl.

The term “sulfonyl derivative” as used herein, is defined as including a group of the formula —SO2—R11, wherein R11 is as defined above except for “sulfonyl derivative”. Non-limiting examples are alkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl and arylsulfonyl.

The term “sulfinyl derivative” as used herein, is defined as including a group of the formula —SO—R11, wherein R11 is as defined above except for “sulfinyl derivative”. Non-limiting examples are alkylsulfinyl, alkenylsulfinyl, alkynylsulfinyl and arylsulfinyl.

Preferred alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, iso or ter-butyl, and 2,2,2-trimethylethyl each optionally substituted by at least one substituent selected from the group consisting of halogen, hydroxy, thiol, amino, nitro and cyano, such as trifluoromethyl, trichloromethyl, 2,2,2-trichloroethyl, 1,1-dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl.

The term “alkenyl” as used herein, is defined as including both branched and unbranched, unsaturated hydrocarbon radicals having at least one double bond such as ethenyl (=vinyl), 1-methyl-1-ethenyl, 2,2-dimethyl-1-ethenyl, 1-propenyl, 2-propenyl (=allyl), 1-butenyl, 2-butenyl, 3-butenyl, 4-pentenyl, 1-methyl-4-pentenyl, 3-methyl-1-pentenyl, 1-hexenyl, 2-hexenyl, and the like and being optionally substituted by at least one substituent selected from the group consisting of halogen, hydroxy, thiol, amino, nitro, cyano, aryl and heterocycle such as mono- and di-halo vinyl where halo is fluoro, chloro or bromo.

The term “alkynyl” as used herein, is defined as including a monovalent branched or unbranched hydrocarbon radical containing at least one carbon-carbon triple bond, for example ethynyl, 2-propynyl (=propargyl), and the like and being optionally substituted by at least one substituent selected from the group consisting of halogen, hydroxy, thiol, amino, nitro, cyano, aryl and heterocycle, such as haloethynyl.

The term “hydroxy”, as used herein, represents a group of the formula —OH.

The term “thiol”, as used herein, represents a group of the formula —SH.

The term “cyano”, as used herein, represents a group of the formula —CN.

The term “nitro”, as used herein, represents a group of the formula —NO2.

The term “nitrooxy”, as used herein, represents a group of the formula —ONO2.

The term “amino”, as used herein, represents a group of the formula —NH2.

The term “azido”, as used herein, represents a group of the formula —N3.

The term “carboxy”, as used herein, represents a group of the formula —COOH.

The term “sulfonic acid”, as used herein, represents a group of the formula —SO3H.

The term “sulfonamide”, as used herein, represents a group of the formula —SO2NH2.

The term “ester”, as used herein is defined as including a group of formula —COO—R11 wherein R11 is as defined above except oxy derivative, thio derivative or amino derivative.

The term “ether” is defined as including a group selected from C1-50-straight or branched alkyl, or C2-50-straight or branched alkenyl or alkynyl groups or a combination of the same, interrupted by one or more oxygen atoms.

The term “amido” is defined as including a group of formula —CONH2 or —CONHR11 or —CONR11R12 wherein R11 and R12 are as defined above.

The term “heterocycle”, as used herein is defined as including an aromatic or non aromatic cyclic alkyl, alkenyl, or alkynyl moiety as defined above, having at least one O, S and/or N atom interrupting the carbocyclic ring structure and optionally, one of the carbon of the carbocyclic ring structure may be replaced by a carbonyl. Non-limiting examples of aromatic heterocycles are pyridyl, furyl, pyrrolyl, thienyl, isothiazolyl, imidazolyl, benzimidazolyl, tetrazolyl, quinazolinyl, quinolizinyl, naphthyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, quinolyl, isoquinolyl, isobenzofuranyl, benzothienyl, pyrazolyl, indolyl, indolizinyl, purinyl, isoindolyl, carbazolyl, thiazolyl, 1,2,4-thiadiazolyl, thieno (2,3-b) furanyl, furopyranyl, benzofuranyl, benzoxepinyl, isooxazolyl, oxazolyl, thianthrenyl, benzothiazolyl, or benzoxazolyl, cinnolinyl, phthalazinyl, quinoxalinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenothiazinyl, furazanyl, isochromanyl, indolinyl, xanthenyl, hypoxanthinyl, pteridinyl, 5-azacytidinyl, 5-azauracilyl, triazolopyridinyl, imidazolopyridinyl, pyrrolopyrimidinyl, and pyrazolopyrimidinyl optionally substituted by alkyl or as described above for the alkyl groups. Non-limiting examples of non aromatic heterocycles are tetrahydrofuranyl, tetrahydropyranyl, piperidinyl, piperidyl, piperazinyl, imidazolidinyl, morpholino, morpholinyl, 1-oxaspiro (4.5) dec-2-yl, pyrrolidinyl, 2-oxo-pyrrolidinyl, sugar moieties (i.e. glucose, pentose, hexose, ribose, fructose, which may also be substituted) or the same which can optionally be substituted with any suitable group, including but not limited to one or more moieties selected from lower alkyl, or other groups as described above for the alkyl groups. The term “heterocycle” also includes bicyclic, tricyclic and tetracyclic, spiro groups in which any of the above heterocyclic rings is fused to one or two rings independently selected from an aryl ring, a cyclohexane ring, a cyclohexene ring, a cyclopentane ring, a cyclopentene ring or another monocyclic heterocyclic ring or where a monocyclic heterocyclic group is bridged by an alkylene group, such as quinuclidinyl, 7-azabicyclo(2.2.1)heptanyl, 7-oxabicyclo(2.2.1) heptanyl, 8-azabicyclo(3.2.1)octanyl.

In the above definitions it is to be understood that when a substituent such as R2, R3, R4, R2a, R3a, R4a, R5, R7, R8, is attached to the rest of the molecule via a heteroatom or a carbonyl, a straight- or branched chain, C1-12-, preferably C1-4-alkylene or C2-12, preferably C2-4-alkenylene or -alkynylene bridge may optionally be interposed between the heteroatom or the carbonyl and the point of attachment to the rest of the molecule.

Examples of preferred R1 groups are methyl, ethyl, propyl, isopropyl, butyl, iso- or ter-butyl, 2,2,2-trimethylethyl each optionally attached via a methylene bridge or the same substituted by at least one halogen atom such as trifluoromethyl, trichloromethyl, 2,2,2-trichloroethyl, 1,1-dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl.

Examples of preferred R2 and R2a groups are independently hydrogen, halogen or methyl, ethyl, propyl, isopropyl, butyl, iso or ter-butyl, 2,2,2-trimethylethyl or the same substituted by at least one halogen atom such as trifluoromethyl, trichloromethyl, 2,2,2-trichloroethyl, 1,1-dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl.

Especially at least one and most preferably both of R2 and R2a are hydrogen.

Examples of preferred R3a, R4 and R4a groups are independently hydrogen, halogen or methyl, ethyl, propyl, isopropyl, butyl, iso or ter-butyl, 2,2,2-trimethylethyl or the same substituted by at least one halogen atom such as trifluoromethyl, trichloromethyl, 2,2,2-trichloroethyl, 1,1-dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl.

Especially at least one and most preferably both of R4 and R4a are hydrogen.

R3a is particularly hydrogen or alkyl, especially lower alkyl and is most preferably hydrogen.

Preferably R3 is hydrogen, C1-12-alkyl, especially C1-6-alkyl, each optionally substituted by one or more substituents selected from hydroxy, halogen, cyano, thiocyanato or alkoxy and attached to the ring either directly or via a thio, sulfinyl, sulfonyl, carbonyl or oxycarbonyl group and optionally, a C1-4-alkylene bridge, particularly methylene; C2-6-alkenyl or -alkynyl, especially C2-3-alkenyl or -alkynyl each optionally substituted by one or more halogens; azido; cyano; amido; carboxy; triazolyl, tetrazolyl, pyrrolidinyl, pyridyl, 1-oxidopyridyl, thiomorpholinyl, benzodioxolyl, furyl, oxazolyl, pyrimidinyl, pyrrolyl, thiadiazolyl, thiazolyl, thienyl or piperazinyl each optionally substituted by one or more substituents selected from halogen, C1-6-alkyl and phenyl and attached to the ring either directly or via a carbonyl group or a C1-4-alkylene bridge, particularly methylene; naphthyl; or phenyl, phenylalkyl or phenylalkenyl each optionally substituted by one or more substituents selected from halogen, C1-6-alkyl, C1-6 haloalkyl, C1-6-alkoxy, C1-6-alkylthio, amino, azido, phenyl and nitro and each attached to the ring either directly or via an oxy, sulfonyl, sulfonyloxy, carbonyl or carbonyloxy group and optionally additionally a C1-4-alkylene bridge, particularly methylene.

Also, preferably, R3 is C1-6-alkyl optionally substituted by one or more substituents selected from halogen, thiocyanato, azido, alkoxy, alkylthio, phenylsulfonyl; nitrooxy; C2-3-alkenyl or -alkynyl each optionally substituted by one or more halogens or by acetyl; tetrazolyl, pyridyl, furyl, pyrrolyl, thiazolyl or thienyl; or phenyl or phenylalkyl each optionally substituted by one or more substituents selected from halogen, C1-6-alkyl, C1-6 haloalkyl, C1-6-alkoxy, amino, azido, phenyl and nitro and each attached to the ring either directly or via a sulfonyloxy and optionally additionally a C1-4-alkylene bridge, particularly methylene.

Other examples of preferred R3 groups are hydrogen, halogen or methyl, ethyl, propyl, isopropyl, butyl, iso or ter-butyl, 2,2,2-trimethylethyl or the same substituted by at least one halogen atom such as trifluoromethyl, trichloromethyl, 2,2,2-trichloroethyl, 1,1-dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl.

R3 is especially C1-4-alkyl optionally substituted by one or more substituents selected from halogen, thiocyanato or azido; C2-5-alkenyl or -alkynyl, each optionally substituted by one or more halogens; thienyl; or phenyl optionally substituted by one or more substituents selected from halogen, C1-6-alkyl, C1-6 haloalkyl or azido.

Further examples of preferred R3 groups are C1-6 alkyl and C2-6 haloalkenyl.

Especially at least one and most preferably both of R5 and R6 are hydrogen. Preferably R7 is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, iso or tert-butyl, 2,2,2-trimethylethyl, methoxy, ethoxy, phenyl, benzyl or the same substituted by at least one halogen atom such as trifluoromethyl, chlorophenyl.

Preferably R7 is hydrogen, methyl or ethyl especially hydrogen.

Preferably R8 is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, iso or ter-butyl, 2,2,2-trimethylethyl, phenyl, benzyl or the same substituted by at least one halogen atom such as trifluoromethyl, chlorobenzyl.

Preferably R8 is hydrogen or methyl.

Combinations of one or more of these preferred compound groups are especially preferred.

A particular group of compounds of formula I (Compounds 1A) comprises those wherein,

R3a is hydrogen, alkyl or aryl (especially with the proviso that when R3a is hydrogen, R3 other than methyl);

or R3R3a form a cycloalkyl;

and R2, R2a, R4 and R4a are each hydrogen.

Within the compounds of formula I,

R1 is preferably alkyl especially C1-12-more particularly C1-6-alkyl and is most preferably ethyl;

R2, R3a and R4a are preferably hydrogen;

R3 is preferably selected from hydrogen; C1-12-alkyl, especially C1-6-alkyl, each optionally substituted by one or more substituents selected from hydroxy, halogen, cyano, thiocyanato or alkoxy and attached to the ring either directly or via a thio, sulfinyl, sulfonyl, carbonyl or oxycarbonyl group and optionally additionally a C1-4-alkylene bridge, particularly methylene; C2-6-alkenyl or -alkynyl, especially C2-3-alkenyl or -alkynyl, each optionally substituted by one or more halogens; azido; cyano; amido; carboxy; triazolyl, tetrazolyl, pyrrolidinyl, pyridyl, 1-oxidopyridyl, thiomorpholinyl, benzodioxolyl, furyl, oxazolyl, pyrimidinyl, pyrrolyl, thiadiazolyl, thiazolyl, thienyl or piperazinyl each optionally substituted by one or more substituents selected from halogen, C1-6-alkyl and phenyl and attached to the ring either directly or via a carbonyl group or a C1-4-alkylene bridge, particularly methylene; naphthyl; or phenyl, phenylalkyl or phenylalkenyl each optionally substituted by one or more substituents selected from halogen, C1-6-alkyl, C1-6 haloalkyl, C1-6-alkoxy, C1-6-alkylthio, amino, azido, phenyl and nitro and each attached to the ring either directly or via an oxy, sulfonyl, sulfonyloxy, carbonyl or carbonyloxy group and optionally additionally a C1-4-alkylene bridge, particularly methylene;

A further group of compounds of formula I (Compounds 1C) comprises those in racemic form wherein, when X is —CONR5R6 and R1 is hydrogen, methyl, ethyl or propyl, then substitution on the pyrrolidine ring is other than mono-, di-, or tri-methyl or mono-ethyl.

A further group of compound of formula I (Compounds 1D) comprises those in racemic form wherein, when X is —CONR5R6 and R1 is hydrogen or C1-6-alkyl, C2-6-alkenyl or -alkynyl or cycloalkyl, each unsubstituted, then substitution in the ring is other than by alkyl, alkenyl or alkynyl, each unsubstituted.

A further particular group of compounds of formula I (Compounds 1E) comprises those wherein,

In the above formula, at least one substituent R1 to R5 is different from hydrogen. Some non-substituted compounds are referred to in U.S. Pat. Nos. 5,468,733 and 5,516,759. U.S. Pat. No. 5,468,733 refers to non-ring substituted 2-oxo-1-pyrrolidinyl and 2-oxo-1-piperidinyl derivatives as inhibitors of the oncogene Ras protein. In particular, these compounds block the ability of Ras to transform normal cells to cancer cells, and therefore can be included in several chemotherapeutic compositions for treating cancer.

U.S. Pat. No. 5,516,759 refers to non-ring substituted 2-oxo-1-pyrrolidinyl, 2-oxo-1-piperidinyl and azepanyl derivatives present at the N-terminus of dodecapeptides possessing LHRH (luteinizing hormone-releasing hormone) antagonistic activity. Such LHRH antagonists are useful in the treatment of a variety of conditions in which suppression of sex steroids plays a key role including contraception, delay of puberty, treatment of benign prostatic hyperplasia a. o.

In the definitions set forth below, unless otherwise stated, R11 and R12 are the same or different and each is independently amido, alkyl, alkenyl, alkynyl, acyl, ester, ether, aryl, aralkyl. heterocycle or an oxy derivative, thio derivative, acyl derivative, amino derivative, sulfonyl derivative, or sulfinyl derivative, each optionally substituted with any suitable group, including, but not limited to, one or more moieties selected from lower alkyl or other groups as described below as substituents for alkyl.

The term “thio derivative”, as used herein, is defined as including —S—R11 groups wherein R11 is as defined above except for “thio derivative”. Non-limiting examples are alkylthio, alkenylthio, alkynylthio and arylthio.

The term “amino derivative”, as used herein, is defined as including —NHR11 or —NR11R12 groups wherein R11 and R12 are as defined above. Non-limiting examples are mono- or di-alkyl-, alkenyl-, alkynyl- and arylamino or mixed amino.

The term “sulfonyl derivative”, as used herein, is defined as including a group of the formula —SO2—R11, wherein R11 is as defined above except for “sulfonyl derivative”. Non-limiting examples are alkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl and arylsulfonyl.

The term “sulfinyl derivative”, as used herein, is defined as including a group of the formula —SO—R11, wherein R11 is as defined above except for “sulfinyl derivative”. Non-limiting examples are alkylsulfinyl, alkenylsulfinyl, alkynylsulfinyl and arylsulfinyl.

Preferred are alkyl groups containing 1 to 7 carbon atoms, each optionally substituted by one or more substituents selected from hydroxy, halogen, cyano, thiocyanato, alkoxy, azido, alkylthio, cyclopropyl, acyl and phenyl. Most preferred are C1-4 alkyl and C3-7 cycloalkyl, each optionally substituted by one or more hydroxy, halogen, lower alkyl or/and azido.

The term “lower alkyl”, as used herein, and unless otherwise specified, refers to C1 to C7 saturated straight, branched or cyclic hydrocarbon. Non limiting examples are methyl, ethyl, propyl, isopropyl, butyl, tertiobutyl, pentyl, cyclopropyl, cyclopentyl, isopentyl, neopentyl, hexyl, isohexyl, cyclohexyl, 3-methypentyl, 2,2-dimethylbutyl, optionally substituted with any suitable group, including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferably, lower alkyl is methyl.

The term “alkenyl”, as used herein, is defined as including both branched and unbranched, unsaturated hydrocarbon radicals having at least one double bond, and being optionally substituted by at least one substituent selected from the group consisting of halogen, hydroxy, thiol, amino, thiocyanato, azido, alkylthio, cycloalkyl, acyl, nitro, cyano, aryl and heterocycle.

The term “alkynyl” as used herein, is defined as including a monovalent branched or unbranched hydrocarbon radical containing at least one carbon-carbon triple bond, for example ethynyl, 2-propynyl (=propargyl), and the like, and being optionally substituted by at least one substituent selected from the group consisting of halogen, hydroxy, thiol, amino, nitro, cyano, aryl, heterocycle, thiocyanato, azido, alkylthio, alkyl and acyl.

Preferred alkynyl groups are C2-12 alkynyl, especially C2-6 alkynyl, optionally being substituted by one or more substituents selected from halogen, cyano, thiocyanato, azido, alkylthio, acyl, aryl such as phenyl and alkyl, preferably cycloalkyl.

Groups where branched derivatives are conventionally qualified by prefixes such as “n”, “sec”, “iso” and the like (e.g. “n-propyl”, “sec-butyl”) are in the n-form unless otherwise stated.

The term “aryl”, as used herein, is defined as including an organic radical derived from an aromatic hydrocarbon consisting of at least one ring, most often 1 to 3 rings and generally containing 6-30 carbon atoms by removal of one hydrogen, such as phenyl and naphthyl, each optionally substituted by one or more substituents independently selected from halogen, hydroxy, thiol, amino, nitro, cyano, acyl, acyloxy, sulfonyl, sulfinyl, alkylamino, carboxy, ester, ether, amido, azido, sulfonic acid, sulfonamide, alkylsulfonyl, alkylsulfinyl, C1-6-alkylthio, oxyester, oxyamido, aryl, C1-6-alkoxy, C6-10-aryloxy, C1-6-alkyl, C1-6-haloalkyl. Aryl radicals are preferably monocyclic or bicyclic containing 6-10 carbon atoms. Preferred aryl groups are phenyl and naphthyl each optionally substituted by one or more substituents independently selected from halogen, nitro, amino, azido, C1-6-alkoxy, C1-6-alkyl, C1-6-haloalkyl, sulfonyl and phenyl.

Preferred aryl is phenyl, optionally substituted by one or more halogen, lower alkyl, azido or nitro, such as 3-chlorophenyl and 3-azidophenyl.

The term “halogen”, as used herein, includes an atom of Cl, Br, F, I.

The term “hydroxy”, as used herein, represents a group of the formula —OH.

The term “thiol”, as used herein, represents a group of the formula —SH.

The term “cyano”, as used herein, represents a group of the formula —CN.

The term “nitro”, as used herein, represents a group of the formula —NO2.

The term “nitrooxy”, as used herein, represents a group of the formula —ONO2.

The term “amino”, as used herein, represents a group of the formula —NH2.

The term “azido”, as used herein, represents a group of the formula —N3.

The term “carboxy”, as used herein, represents a group of the formula —COOH.

The term “sulfonic acid”, as used herein, represents a group of the formula —SO3H.

The term “sulfonamide”, as used herein, represents a group of the formula —SO2NH2.

The term “ester”, as used herein, is defined as including a group of formula —COO—R11 wherein R11 is as defined above except oxy derivative, thio derivative or amino derivative. Preferred are esters of formula —COOR11 wherein R11 is selected from C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl and aryl. Most preferred are esters where R11 is a lower alkyl, especially methyl.

The term “ether” is defined as including a group selected from C1-50-straight or branched alkyl, or C2-50-straight or branched alkenyl or alkynyl groups or a combination of the same, interrupted by one or more oxygen atoms.

The term “amido” is defined as including a group of formula —CONH2 or —CONHR11 or —CONR11R12 wherein R11 and R12 are as defined above.

The term “heterocycle”, as used herein, is defined as including an aromatic or non aromatic cyclic alkyl, alkenyl, or alkynyl moiety as defined above, having at least one O, S and/or N atom interrupting the carbocyclic ring structure and optionally, one of the carbon of the carbocyclic ring structure may be replaced by a carbonyl, and optionally being substituted with any suitable group, including but not limited to one or more moieties selected from lower alkyl, or other groups as described above for the alkyl groups. Non-limiting examples of heterocycles are pyridyl, furyl, pyrrolyl, thienyl, isothiazolyl, triazolyl, imidazolyl, benzimidazolyl, tetrazolyl, quinazolinyl, quinolizinyl, naphthyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, quinolyl, isoquinolyl, isobenzofuranyl, benzothienyl, pyrazolyl, indolyl, indolizinyl, purinyl, isoindolyl, carbazolyl, thiazolyl, 1,2,4-thiadiazolyl, thiomorpholinyl, thieno (2,3-b) furanyl, furopyranyl, benzofuranyl, benzoxepinyl, isooxazolyl, oxazolyl, thianthrenyl, benzothiazolyl, or benzoxazolyl, cinnolinyl, phthalazinyl, quinoxalinyl, 1-oxidopyridyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenothiazinyl, furazanyl, benzodioxolyl, isochromanyl, indolinyl, xanthenyl, hypoxanthinyl, pteridinyl, 5-azacytidinyl, 5-azauracilyl, triazolopyridinyl, imidazolopyridinyl, pyrrolopyrimidinyl, pyrazolopyrimidinyl, tetrahydropyranyl, tetrahydropyranyl, piperidinyl, piperidyl, piperazinyl, imidazolidinyl, morpholino, morpholinyl, 1-oxaspiro (4.5) dec-2-yl, pyrrolidinyl, 2-oxo-pyrrolidinyl, sugar moieties (i.e. glucose, pentose, hexose, ribose, fructose, which may also be substituted) optionally substituted by alkyl or as described above for the alkyl groups. The term“heterocycle” also includes bicyclic, tricyclic and tetracyclic, spiro groups in which any of the above heterocyclic rings is fused to one or two rings independently selected from an aryl ring, a cyclohexane ring, a cyclohexene ring, a cyclopentane ring, a cyclopentene ring or another monocyclic heterocyclic ring or where a monocyclic heterocyclic group is bridged by an alkylene group, such as quinuclidinyl, 7-azabicyclo(2.2.1) heptanyl, 7-oxabicyclo(2.2.1) heptanyl, 8-azabicyclo(3.2.1) octanyl.

More preferably the heterocycle is selected from tetrazolyl, pyrrolidinyl, pyridyl, furyl, pyrrolyl, thiazolyl and thienyl, each optionally substituted by one or more substituents selected from halogen, alkyl, halogen substituted alkyl, acyl, alkoxy, nitro, amino and phenyl, and especially from 2- and 3-thienyl, optionally substituted by one or more halogen, acyl such as formyl, cyano and/or lower alkyl, such as methyl.

In the above definitions it is to be understood that when a substituent such as R1, R2, R3, R4, R5, R7, R8, R9, R10 is attached to the rest of the molecule via a heteroatom or a carbonyl, a straight- or branched chain, C1-12-, preferably C1-4-alkylene or C2-12, preferably C2-4-alkenylene or -alkynylene bridge may optionally be interposed between the heteroatom or the carbonyl and the point of attachment to the rest of the molecule.

The term “R substituent” refers to R1, R2, R3, R4 or R5, independently.

According to a preferred embodiment, a compound of formula I is as defined above wherein n represents 0. The compound is a 6-ring structure (2-thioxo- or 2-oxo-piperidinyl derivative) wherein R1 is not existent since n=0, and is depicted by the formula (I-A).

According to a following embodiment, the compound of formula I is as defined above wherein n represents 1. The compound is a 7-ring structure (2-thioxo- or 2-oxo-azepanyl derivative) wherein R1 is existent since n=1 and depicted by the formula (I-B).

According to a more preferred embodiment, said compound is as defined above wherein n=0, R3 and/or R4 are different from hydrogen and R2 and R5 represent hydrogen.

According to another more preferred embodiment, said compound is as defined above wherein n=1, R2, R3 and/or R4 are different from hydrogen and wherein R1 and R5 represent hydrogen.

According to a yet more preferred embodiment, said compound is as defined above wherein only one R substituent chosen from R3 or R4 when n=0 or from R2, R3 or R4 when n=1, is different from hydrogen and the remaining R substituent(s) is/are hydrogen. We hereby refer to a mono-substituted 2-thioxo- or 2-oxo-piperidinyl or 2-thioxo- or 2-oxo-azepanyl derivatives.

According to another preferred embodiment, compounds of formula I are as defined above wherein A1 represents an oxygen atom. We hereby refer to 2-oxo-piperidinyl or 2-oxo-azepanyl derivatives.

According to another preferred embodiment, compounds of formula I are as defined above wherein X is CONR7R8, especially CONH2. We hereby refer to amido derivatives of 2-oxo (or thioxo)-piperidinyl or 2-oxo (or thioxo)-azepanyl.

According to another preferred embodiment, compounds of formula I are as defined above wherein R6 represents hydrogen, C1-4 alkyl, or a CH2—R6a group wherein R6a represents a heterocycle. Most preferably R6 is a C1-4 alkyl, especially ethyl. When R6 is ethyl we refer to 2-(2-oxo (or thioxo)-1-piperidinyl)butanamide or 2-(2-oxo (or thioxo)-1-azepanyl)butanamide derivatives.

According to another preferred embodiment, compounds of formula I are as defined above wherein the carbon atom to which R6 is attached is of the S configuration. In case where R6 is ethyl, A is oxygen and X is CONR7R8 we refer then to (2S)-2-(2-oxo-1-piperidinyl)butanamide or (2S)-2-(2-oxo-1-azepanyl)butanamide derivatives.

According to a preferred embodiment, the compound is as defined above wherein R2 when n=1, R3 and R4 are the same or different and each is independently hydrogen, halogen, nitro, nitrooxy, cyano, carboxy, amido, sulfonic acid, sulfonamide, alkyl, alkenyl, alkynyl, ester, ether, aryl, heterocycle, acyl derivative, sulfonyl derivative or sulfinyl derivative;

According to this preferred embodiment, the compound is generally such that when R6 is benzyl, X is —COOCH3 and n=1, R2 is different from methyl when R3 and R4 are both hydrogen and R4 is different from methyl when R2 and R3 are both hydrogen.

According to another preferred embodiment, the compound is as defined above wherein R2 when n=1, R3 and R4 are the same or different and each is independently hydrogen; cyano; carboxy; amido;

According to another preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R2, R3 and R4 when n=1 or from the group R3 and R4 when n=0, represents independently C1-4-alkyl or C3-7-cycloalkyl, optionally substituted by one or more halogen, hydroxy, lower alkyl and/or azido.

According to another preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R2, R3 and R4 when n=1 or from the group R3 and R4 when n=0, represents independently vinyl, optionally substituted by one or more halogen or/and lower alkyl.

According to another preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R2, R3 and R4 when n=1 or from the group R3 and R4 when n=0, represents independently ethynyl, propynyl or butynyl, optionally substituted by one or more halogen and/or lower alkyl.

According to another preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R2, R3 and R4 when n=1 or from the group R3 and R4 when n=0, represents independently phenyl, optionally substituted by one or more halogen, lower alkyl, azido and/or nitro.

According to another preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R2, R3 and R4 when n=1 or from the group R3 and R4 when n=0, represents independently 2- or 3-thienyl, optionally substituted by one or more halogen, acyl, cyano or/and lower alkyl.

According to a particular preferred embodiment, the compound is as defined above wherein at least one of the R substituents chosen from the group R3, R4 and R2 when n=1 or from the group R3 and R4 when n=0, is hydroxymethyl, propyl, butyl, 3,3,3-trifluoropropyl, 2,2,2-trifluoroethyl, cyclopropylmethyl, iodomethyl, azidomethyl, 2-thienyl, 3-thienyl, phenyl, 3-chlorophenyl, 3-azidophenyl, 2,2-difluorovinyl, 2,2-dibromovinyl, 2,2-dichlorovinyl, 2-ethynyl, 5-methyl-2-thienyl, 5-formyl-2-ethynyl, 5-cyano-2-thienyl, 3-bromo-2-thienyl, 4-methyl-2-thienyl, 3,3,3-trifluoro-1-propynyl, 1-propynyl, cyclopropylethynyl, 3-methyl-1-butynyl, 1-butynyl, 2,2-difluoropropyl, 2-chloro-2,2-difluoroethyl, 2-bromo-2,2-difluoroethyl and 2-iodo-2,2-difluoroethyl.

According to yet another preferred embodiment, the compound is as defined above wherein R1, R2, R4 and R5 are hydrogen.

According to even another preferred embodiment, the compound is as defined above wherein R1, R2, R3 and R5 are hydrogen.

According to even another preferred embodiment, the compound is as defined above wherein n=1 and R1, R3, R4 and R5 are hydrogen.

In all the above-mentioned scopes when the carbon atom to which R6 is attached is asymmetric it is preferably in the “S”-configuration.

Representative compounds useful in the methods and compositions of this invention as defined above are selected from the group consisting of

2-[5-(hydroxymethyl)-2-oxo-1-piperidinyl]butanamide,

2-(2-oxo-5-propyl-1-piperidinyl)butanamide,

2-[2-oxo-5-(3,3,3-trifluoropropyl)-1-piperidinyl]butanamide,

2-[5-(cyclopropylmethyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(iodomethyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(azidomethyl)-2-oxo-1-piperidinyl]butanamide,

2-(2-oxo-5-phenyl-1-piperidinyl)butanamide,

2-[2-oxo-5-(2-thienyl)-1-piperidinyl]butanamide,

2-[2-oxo-5-(3-thienyl)-1-piperidinyl]butanamide,

2-[5-(3-chlorophenyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(3-azidophenyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2,2-difluorovinyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2,2-dibromovinyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2,2-dichlorovinyl)-2-oxo-1-piperidinyl]butanamide,

2-(5-ethynyl-2-oxo-1-piperidinyl)butanamide,

2-[5-(5-methyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(5-formyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(5-cyano-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(3-bromo-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(4-methyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[2-oxo-5-(3,3,3-trifluoro-1-propynyl)-1-piperidinyl]butanamide,

2-[2-oxo-5-(1-propynyl)-1-piperidinyl]butanamide,

2-[5-(cyclopropylethynyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(3-methyl-1-butynyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(1-butynyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2,2-difluoropropyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2-chloro-2,2-difluoroethyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(2-bromo-2,2-difluoroethyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(hydroxymethyl)-2-oxo-1-piperidinyl]butanamide,

2-(2-oxo-4-propyl-1-piperidinyl)butanamide,

2-[2-oxo-4-(3,3,3-trifluoropropyl)-1-piperidinyl]butanamide,

2-[4-(cyclopropylmethyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(iodomethyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(azidomethyl)-2-oxo-1-piperidinyl]butanamide,

2-(2-oxo-4-phenyl-1-piperidinyl)butanamide,

2-[2-oxo-4-(2-thienyl)-1-piperidinyl]butanamide,

2-[2-oxo-4-(3-thienyl)-1-piperidinyl]butanamide,

2-[4-(3-chlorophenyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(3-azidophenyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2,2-difluorovinyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2,2-dibromovinyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2,2-dichlorovinyl)-2-oxo-1-piperidinyl]butanamide,

2-(4-ethynyl-2-oxo-1-piperidinyl)butanamide,

2-[4-(5-methyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(5-formyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(5-cyano-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(3-bromo-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(4-methyl-2-thienyl)-2-oxo-1-piperidinyl]butanamide,

2-[2-oxo-4-(3,3,3-trifluoro-1-propynyl)-1-piperidinyl]butanamide,

2-[2-oxo-4-(1-propynyl)-1-piperidinyl]butanamide,

2-[4-(cyclopropylethynyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(3-methyl-1-butynyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(1-butynyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2,2-difluoropropyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2-chloro-2,2-difluoroethyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2-bromo-2,2-difluoroethyl)-2-oxo-1-piperidinyl]butanamide,

2-[4-(2,2,2-trifluoroethyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(hydroxymethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-5-propyl-1-azepanyl)butanamide,

2-[2-oxo-5-(3,3,3-trifluoropropyl)-1-azepanyl]butanamide,

2-[5-(cyclopropylmethyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(iodomethyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(azidomethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-5-phenyl-1-azepanyl)butanamide,

2-[2-oxo-5-(2-thienyl)-1-azepanyl]butanamide,

2-[2-oxo-5-(3-thienyl)-1-azepanyl]butanamide,

2-[5-(3-chlorophenyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(3-azidophenyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2,2-difluorovinyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2,2-dibromovinyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2,2-dichlorovinyl)-2-oxo-1-azepanyl]butanamide,

2-(5-ethynyl-2-oxo-1-azepanyl)butanamide,

2-[5-(5-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(5-formyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(5-cyano-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(3-bromo-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(4-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[2-oxo-5-(3,3,3-trifluoro-1-propynyl)-1-azepanyl]butanamide,

2-[2-oxo-5-(1-propynyl)-1-azepanyl]butanamide,

2-[5-(cyclopropylethynyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(3-methyl-1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2,2-difluoropropyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2-chloro-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2-bromo-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[5-(2,2,2-trifluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(hydroxymethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-6-propyl-1-azepanyl)butanamide,

2-[2-oxo-6-(3,3,3-trifluoropropyl)-1-azepanyl]butanamide,

2-[6-(cyclopropylmethyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(iodomethyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(azidomethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-6-phenyl-1-azepanyl)butanamide,

2-[2-oxo-6-(2-thienyl)-1-azepanyl]butanamide,

2-[2-oxo-6-(3-thienyl)-1-azepanyl]butanamide,

2-[6-(3-chlorophenyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(3-azidophenyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2,2-difluorovinyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2,2-dibromovinyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2,2-dichlorovinyl)-2-oxo-1-azepanyl]butanamide,

2-(6-ethynyl-2-oxo-1-azepanyl)butanamide,

2-[6-(5-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(5-formyl-2-thienyl)-2-oxo-1-azepanyllbutanamide,

2-[6-(5-cyano-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(3-bromo-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(4-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[2-oxo-6-(3,3,3-trifluoro-1-propynyl)-1-azepanyl]butanamide,

2-[2-oxo-6-(1-propynyl)-1-azepanyl]butanamide,

2-[6-(cyclopropylethynyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(3-methyl-1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2,2-difluoropropyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2-chloro-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2-bromo-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[6-(2,2,2-trifluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(hydroxymethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-4-propyl-1-azepanyl)butanamide,

2-[2-oxo-4-(3,3,3-trifluoropropyl)-1-azepanyl]butanamide,

2-[4-(cyclopropylmethyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(iodomethyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(azidomethyl)-2-oxo-1-azepanyl]butanamide,

2-(2-oxo-4-phenyl-1-azepanyl)butanamide,

2-[2-oxo-4-(2-thienyl)-1-azepanyl]butanamide,

2-[2-oxo-4-(3-thienyl)-1-azepanyl]butanamide,

2-[4-(3-chlorophenyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(3-azidophenyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2,2-difluorovinyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2,2-dibromovinyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2,2-dichlorovinyl)-2-oxo-1-azepanyl]butanamide,

2-(4-ethynyl-2-oxo-1-azepanyl)butanamide,

2-[4-(5-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(5-formyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(5-cyano-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(3-bromo-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(4-methyl-2-thienyl)-2-oxo-1-azepanyl]butanamide,

2-[2-oxo-4-(3,3,3-trifluoro-1-propynyl)-1-azepanyl]butanamide,

2-[2-oxo-4-(1-propynyl)-1-azepanyl]butanamide,

2-[4-(cyclopropylethynyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(3-methyl-1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(1-butynyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2,2-difluoropropyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2-chloro-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2-bromo-2,2-difluoroethyl)-2-oxo-1-azepanyl]butanamide,

2-[4-(2,2,2-tritluoroethyl)-2-oxo-1-azepanyl]butanamide.

In some embodiments, compounds useful in the methods and compositions of this invention are selected from the group consisting of:

(2S)-2-[5-(iodomethyl)-2-oxo-1-piperidinyl]butanamide,

(2S)-2-[5-(azidomethyl)-2-oxo-1-piperidinyl]butanamide,

2-(2-oxo-5-phenyl-1-piperidinyl]butanamide,

(2S)-2-[4-(iodomethyl)-2-oxo-1-piperidinyl]butanamide,

2-[5-(iodomethyl)-2-oxo-1-azepanyl]butanamide.

iii) International Patent Application WO 2004/087658:

A compound having the formula I or a pharmaceutically acceptable salt thereof or stereoisomeric forms thereof,

wherein

R1 is hydrogen,

R2 is hydrogen or C1-20-alkyl,

R3 is hydrogen, C1-20-alkyl, C4-8-cycloalkyl, C5-8-cycloalkenyl, aryl, aromatic or non aromatic heterocycle, C1-20-alkoxy, or a group of formula —W—R8, R3a is hydrogen, C1-20-alkyl or a group of formula:

The term “cycloalkyl”, as used herein, refers to a monovalent group of 3 to 18 carbon atoms, preferably 4-8 carbon atoms, derived from a saturated cyclic or polycyclic hydrocarbon which may be substituted by any suitable group including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferred cycloalkyl group is cycloheptyl.

The term “alkylene”, as used herein, represents a divalent alkyl group, having straight or branched moieties, containing 1-12 carbon atoms, preferably 1-6 carbon atoms, and being optionally substituted with any suitable group, including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferred alkylene groups are methylene, ethylene, hydroxyethylene, trimethylene or propylene.

The term “cycloalkenyl”, as used herein, is defined as a cyclic unsaturated hydrocarbon radical having at least one double bond, containing 4-20 carbon atoms, preferably 5-8 carbon atoms, and being optionally substituted with any suitable group, including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferred cycloalkenyl group is 6-(hydroxymethyl)cyclohex-3-en-1-yl.

The term “aryl”, as used herein, is defined as including an organic radical derived from an aromatic hydrocarbon consisting of 1-3 rings and containing 6-30 carbon atoms by removal of one hydrogen, such as phenyl and naphthyl each optionally substituted by 1 to 5 substituents independently selected from halogen, hydroxy, nitro, C1-6-alkyl, C1-6-alkoxy, C1-6-alkylsulfonyl, trifluoromethylthio or pyridinylalkyl. Aryl radicals are preferably phenyl radicals. Preferred aryl groups are phenyl, 3-hydroxyphenyl, 3-fluorophenyl, 3-methylphenyl, 4-methylphenyl, 4-hydroxyphenyl, 4-hydroxy-3-methoxyphenyl, 3-(2-pyridin-2-ylethyl)phenyl, 3,4-dimethylphenyl, 4-tert-butylphenyl, 4-methylsulfonylphenyl, 2-nitrophenyl, 2-chloro-6-fluorophenyl, 2-[(trifluoromethyl)thio]phenyl, 2-chlorophenyl or 4-bromophenyl.

The term “halogen”, as used herein, includes an atom of Cl, Br, F, I.

The term “nitro”, as used herein, represents a group of the formula —NO2.

The term “hydroxy”, as used herein, represents a group of the formula —OH.

The term “alkoxy”, as used herein, represents a group of formula —ORb wherein Rb is an alkyl group, as defined above.

The term “ester”, as used herein, represents a group of formula —COORc wherein Rc is an alkyl group or an aryl group, as defined above.

The term “alkoxycarbonyl”, as used herein, represents a group of formula —COORd wherein Rd is an alkyl group, as defined above.

The term “amino”, as used herein, represents a group of the formula —NH2.

The term “alkylamino”, as used herein, represents a group of formula —NHRe or —NReRf wherein Re and Rf are alkyl group as defined above.

The term alkylsulfonyl, as used herein is defined as representing a group of formula —SO2—Rg, wherein Rg is C1-4-alkyl.

The term “heterocycle”, as used herein is defined as including an aromatic or non aromatic cycloalkyl or cycloalkenyl moiety as defined above, having at least one O, S and/or N atom interrupting the carbocyclic ring structure and optionally, one of the carbon of the carbocyclic ring structure may be replaced by a carbonyl.

Preferably, R3a is hydrogen, methyl or tetrahydrofuran-2-ylmethyl. More preferably, R3a is hydrogen.

In another embodiment, NR3R3a is piperidinyl unsubstituted or substituted by hydroxy; thiomorpholinyl; thiazolidinyl unsubstituted or substituted by C1-4-alkoxycarbonyl; 2,5-dihydro-1H-pyrrol-1-yl; 1,4-dioxa-8-azaspiro[4.5]dec-8-yl; 4-oxooctahydro-1(2H)-quinolinyl; or a group of formula

wherein R14 is pyridinyl; phenyl unsubstituted or substituted by halogen, hydroxy, C1-4-alkyl; or a group of formula —V—R15 wherein V is unsubstituted C1-4-alkylene and R15 is phenyl or morpholinyl.

Combinations of one or more of these preferred compound groups are especially preferred.

In a preferred embodiment, the compound has the formula I or a pharmaceutically acceptable salt thereof or stereoisomeric forms thereof,

wherein R1 is hydrogen,

R2 is hydrogen or C1-4-alkyl,

R3 is hydrogen; C1-6-alkyl unsubstituted or substituted by 1 to 5 substituents selected from halogen, hydroxy, alkoxy, alkoxycarbonyl or alkylamino; C5-7-cycloalkyl; (hydroxymethyl)cyclohexenyl; phenyl unsubstituted or substituted by 1 to 5 substituents selected from halogen, C1-4-alkyl, hydroxy, methoxy, nitro, methylsulfonyl, trifluoromethylthio or pyridinylalkyl; pyridinyl unsubstituted or substituted by methoxy; triazolyl; C1-4-alkoxy; or a group of formula —W—R8,

R3a is hydrogen, C1-4-alkyl or a group of formula

or NR3R3a is piperidinyl unsubstituted or substituted by hydroxy; thiomorpholinyl; thiazolidinyl unsubstituted or substituted by C1-4-alkoxycarbonyl; 2,5-dihydro-1H-pyrrol-1-yl; 1,4-dioxa-8-azaspiro[4.5]dec-8-yl; 4-oxooctahydro-1(2H)-quinolinyl; or a group of formula

R4 is hydrogen,

R5 is hydrogen; nitro; halogen; C1-4-alkyl, unsubstituted or substituted by halogen; or C1-4-alkoxy unsubstituted or substituted by halogen,

R6 is hydrogen, C1-6-allyl or halogen,

R7 is hydrogen, methyl or halogen,

W is C1-4-alkylene unsubstituted or substituted by halogen, hydroxy, C1-4-alkyl or alkoxy; —NH—; or —NHC(═O)—,

In some embodiments, compounds useful in the methods and compositions of this invention are selected from the group consisting of: 2-(5-iodo-2-oxo-2,3-dihydro-1H-indol-1-yl)acetamide; 2-(5-chloro-2-oxo-2,3-dihydro-1H-indol-1-yl) acetamide; 2-(5,7-dibromo-2-oxo-2,3-dihydro-1H-indol-1-yl)acetamide; (2S)-2-(5-chloro-2-oxo-2,3-dihydro-1H-indol-1-yl) propanamide; 2-[2-oxo-5-(trifluoromethyl)-2,3-dihydro-1H-indol-1-yl]acetamide and 2-(5-chloro-7-fluoro-2-oxo-2,3-dihydro-1H-indol-1-yl) acetamide.

In another embodiment, compounds useful in the methods and compositions of this invention are selected from the group consisting of: 2-(5-chloro-2-oxo-2,3-dihydro-1H-indol-1-yl) acetamide and (2S)-2-(5-chloro-2-oxo-2,3-dihydro-1H-indol-1-yl)propanamide.

iv) U.S. Pat. No. 7,244,747:

A compound having the formula I or a pharmaceutically acceptable salt thereof,

The term “cycloalkyl”, as used herein, represents a monovalent group of 3 to 8 carbon atoms, usually 3-6 carbon atoms derived from a saturated cyclic hydrocarbon, which may be substituted by any suitable group including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferred cycloalkyl groups are cyclopropyl and cyclohexyl.

The term “alkenyl” as used herein, represents straight, branched or cyclic unsaturated hydrocarbon radicals or combinations thereof having at least one carbon-carbon double bond, containing 2-12 carbon atoms, preferably usually 2-4 carbon atoms. Alkenyl groups are being optionally substituted with any suitable group, including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Usually an alkenyl group is ethenyl (vinyl) optionally substituted by 1 to 3 halogens. Preferred alkenyl group, in the present case, is 2,2-difluorovinyl.

The term a “alkynyl” as used herein, represents straight, branched or cyclic hydrocarbon radicals or combinations thereof containing at least one carbon-carbon triple bond, containing 2-12 carbon atoms, preferably 2-6 carbon atoms, and being optionally substituted by any suitable group, including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferably an alkynyl group is a halogenoalkynyl group (haloalkynyl group).

Groups qualified by prefixes such as “s”, “i”, “t” and the like (e.g. “i-propyl”, “s-butyl”) are branched derivatives.

The term “heterocycle”, as used herein, is defined as including an aromatic or non aromatic cycloalkyl moiety as defined above, having at least one O, S and/or N atom interrupting the carbocyclic ring structure. Heterocyclic ring moieties can be optionally substituted by alkyl groups or halogens and optionally, one of the carbon of the carbocyclic ring structure may be replaced by a carbonyl. Usually heterocycles are 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-tetrahydrofuranyl, 1H-pyrrol-2-yl, 1-methyl-1H-pyrrol-2-yl, 1H-pyrazol-2-yl, 1H-pyrazol-3-yl, 4-chloro-1-methyl-1H-pyrazol-3-yl, 5-chloro-1,3-dimethyl-1H-pyrazol-4-yl, 1,2,3-thiadiazol-4-yl, 3,5-dimethyl-4-isothiazyl, 1H-imidazol-2-yl, 1-methyl-1H-imidazol-2-yl, 4-methyl-1H-imidazol-5-yl, or 2-methyl-1,3-thiazol-4-yl. Preferred heterocycles are 1H-imidazol-2-yl, 1,2,3-thiadiazol-4-yl, 1H-pyrazol-3-yl, 2-furyl, 3-furyl, 2-thienyl, 1-methyl-1H-pyrrol-2-yl, 1H-pyrrol-2-yl.

The term “halogen”, as used herein, includes an atom of chlorine, bromine, fluorine, iodine. Usually halogens are chlorine, bromine and fluorine. Preferred halogens are fluorine, bromine and chlorine.

The term “hydroxy”, as used herein, represents a group of formula —OH.

The term “alkoxy”, as used herein, represents a group of formula —ORa

wherein Ra is an alkyl group, as defined above. Preferred alkoxy group is methoxy.

The term “aryloxy”, as used herein, represents a group of formula —ORb wherein Rb is an aryl group, as defined above. Preferred aryloxy group is phenoxy.

The term “ester”, as used herein, represents a group of formula —COORc wherein Rc is an alkyl group or aryl group, as defined above. Preferred ester group is methoxycarbonyl.

The term “amido”, as used herein, represents a group of formula —CONH2.

The term “amino”, as used herein, represents a group of formula —NH2.

The term “aminoderivative”, as used herein, represents an alkylamino or an arylamino group, wherein the terms “alkyl” and “aryl” are defined as above.

The term “cyano”, as used herein, represents a group of formula —CN.

The term “nitro”, as used herein, represents a group of formula NO2.

The term “azido”, as used herein, represents a group of formula —N3.

The term “guanidine”, as used herein, represents a group of formula —NHC(═NH)NH2.

The term “alkylthio”, as used herein, represents a group of formula —SRd wherein Rd is an alkyl group, as defined above. Preferred alkylthio group is methylthio.

The term “alkylsulfonyl”, as used herein, represents a group of formula —S(═O)2Re wherein Re is an alkyl group, as defined above. Preferred alkylsulfonyl group is methylsulfonyl.

The term “alkylsulfinyl”, as used herein, represents a group of formula —S(═O)Rf wherein Rf is an alkyl group, as defined above. Preferred alkylsulfinyl group is methylsulfinyl.

The term “arylthio”, as used herein, represents a group of formula —SR9 wherein Rg is an aryl group, as defined above.

The term “arylsulfonyl”, as used herein, represents a group of the formula —S(═O)2Rh wherein Rh is an aryl group, as defined above.

The term “arylsulfinyl”, as used herein, represents a group of the formula —S(═O)Ri wherein Ri is an aryl group, as defined above.

The term “carbamate” as used herein, represents a group of formula —N(H)C(O)ORj, wherein Rj is an alkyl or an aryl, as defined above. Usually carbamate groups are (propoxycarbonyl)amino or (benzyloaxycarbonyl)amino. Preferred carbamate group is (benzyloaxycarbonyl)amino.

The term “alkanoylamino” as used herein, represents a group of the formula —NHC(═O)Rk wherein Rk is an alkyl group, as defined above.

The term “(arylcarbonyl)amino” as used herein, represents a group of the formula —NHC(═O)Rm wherein Rm is an aryl group, as defined above. Preferred (arylcarbonyl)amino is benzoylamino.

In other preferred embodiments, R4, R4a and R5 can form together with the 2-oxo-1-pyrrolidine ring the following 1,3-dihydro-2H-indol-2-one cycle

Usually, R12 is hydrogen or halogen. Preferably R12 is hydrogen; chloro or fluoro. More preferred R12 is hydrogen.

Usually, R13 is hydrogen; C1-3 alkyl; halogen or thiazolyl unsubstituted or substituted by alkyl groups, such as methylthiazolyl. Preferably R13 is hydrogen; chloro; bromo or methyl. Most preferred R13 is chloro; bromo or methyl.

Usually R14 is hydrogen.

Usually, R15 is hydrogen.

Combinations of one or more of these preferred compound groups are especially preferred.

Generally, among the embodiments, the compounds of formula I, or pharmaceutically acceptable salts thereof, are those wherein

In some embodiments, compounds useful in the methods and compositions of this invention are selected from the group consisting of: (−)-4-(3-azido-2,4-difluorophenyl)-1-(1H-imidazol-1-ylmethyl)pyrrolidin-2-1-one; (+)-4-(3-azido-2,4-difluorophenyl)-1-(1H-imidazol-1-ylmethyl)pyrrolidin-2-one; 4-(3-azido-2,4-difluorophenyl)-1-(1H-imidazol-1-ylmethyl)pyrrolidin-2-one.

The term “cycloalkyl”, as used herein, represents a monovalent group of 3 to 8, preferably 3 to 6 carbon atoms derived from a saturated cyclic hydrocarbon, which may be substituted by any suitable group including but not limited to one or more moieties selected from groups as described above for the alkyl groups. Preferred cycloalkyl group is cyclohexyl.

The term “aryl” as used herein, is defined as a phenyl group optionally substituted by 1 to 4 substituents independently selected from halogen, amino, nitro, alkoxy or aminosulfonyl. Preferred aryl groups are phenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 3-methoxyphenyl, 3-nitrophenyl, 3-aminophenyl or 4-(aminosulfonyl)phenyl.

The term “phenyl”, as used herein, represents an aromatic hydrocarbon group of formula —C6H5.

The term “benzyl group”, as used herein, represents a group of formula —CH2-aryl. Preferred benzyl groups are benzyl, 2-bromobenzyl, 3-bromobenzyl, 4-bromobenzyl, 3-methoxybenzyl, 3-nitrobenzyl, 3-aminobenzyl or 4-(aminosulfonyl)benzyl. More preferred benzyl groups are benzyl, 3-bromobenzyl, 3-methoxybenzyl, 3-nitrobenzyl or 3-aminobenzyl. Most preferred alkyl groups are 3-methoxybenzyl or 3-nitrobenzyl.

The term “halogen”, as used herein, represents an atom of fluorine, chlorine, bromine, or iodine. Preferred halogen is bromine.

The term “hydroxy”, as used herein, represents a group of formula —OH.

The term “cyano”, as used herein, represents a group of formula —CN.

The term “amino”, as used herein, represents a group of formula —NH2.

The term “ethynyl”, as used herein, represents a group of formula —C≡CH.

The term “alkoxy”, as used herein, represents a group of formula —ORa wherein Ra is an alkyl group, as defined above. Preferred alkoxy group is methoxy.

The term “nitro”, as used herein, represents a group of formula —NO2.

The term “amido”, as used herein, represents a group of formula —C(═O)NH2.

The term “acyl”, as used herein, represents a group of formula —C(═O)Rb wherein Rb is an alkyl group, as defined here above. Preferred acyl group is acetyl (—C(═O)Me).

The term “alkoxycarbonyl (or ester)”, as used herein, represents a group of formula COORc wherein Rc is an alkyl group; with the proviso that Rc does not represent an alkyl alpha-substituted by hydroxy. Preferred alkoxycarbonyl group is ethoxycarbonyl.

The term “heterocycle”, as used herein, represents a 5-membered ring containing one or two heteroatoms selected from O or N. The heterocycle may be substituted by one or two C1-4 alkyl or nitro. Preferred heterocycles are (3,5-dimethylisoxazol-4-yl) or (5-nitro-2-furyl). Most preferred heterocycle is (5-nitro-2-furyl).

Generally R2 is hydrogen or C1-4 alkyl. Usually R2 is hydrogen or unsubstituted C1-4 alkyl. Preferably R2 is hydrogen, methyl or n-butyl. More preferably, R2 is methyl.

Generally R3 is a group of formula —CHR5R6 or a benzyl group. Preferably R3 is 3-pentyl, 1-(aminocarbonyl)propyl, 1-(ethoxycarbonyl)propyl or 3-bromobenzyl. Most preferably R3 is 1-(ethoxycarbonyl)propyl.

In some embodiments, the compounds are those having formula I, and their enantiomers, diastereoisomers and mixtures thereof (including all possible mixtures of stereoisomers), or pharmaceutically acceptable salts thereof,

with the proviso that when R1 is hydrogen, R2 is methyl, R3 is —CHR5, R6, R6 is ethoxycarbonyl and R5 is ethyl, then R4 is different from n-propyl, i-propyl, n-pentyl, n-heptyl, 3-bromobenzyl, 4-chlorobenzyl, 4-methylbenzyl or 2-phenylethyl.

In the above embodiment, preferably, when R3 is a benzyl group, then R4 is C1-8 alkyl optionally substituted by alkoxycarbonyl.

In the above embodiment, preferably, when R3 is a group of formula —CHR5R6, then R4 is C1-8 alkyl optionally substituted by C3-6 cycloalkyl, aryl or heterocycle.

In some embodiments, compounds useful in the methods and compositions of this invention are selected from the group consisting of: ethyl 2-{[7-(3-methoxybenzyl)-3-methyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl]thio}butanoate; ethyl 2-{[3-methyl-7-(3-nitrobenzyl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl]thio}butanoate; and ethyl 2-({3-methyl-7-[(5-nitro-2-furyl)methyl]-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl}thio)butanoate.

The compounds or agents or pharmaceutically acceptable salts thereof useful for the methods and compositions of this invention, also include those referred to in: i) US Patent Application 2008/0081832; ii) International Patent Application WO 2006/128692; iii) International Patent Application WO 2006/128693; iv) UK Patent No. 1,039,113; and v) UK Patent No. 1,309,692.

In one aspect of the invention, the SV2A inhibitor is levetiracetam. Levetiracetam refers to the International Union of Pure and Applied Chemistry (IUPAC) name of the compound (2S)-2-(2-oxopyrrolidin-1-yl) butanamide). Levetiracetam is a widely used antiepileptic drug. Levetiracetam binds to a specific site in the CNS: the synaptic vesicle protein 2A (SV2A) (See.e.g., Noyer et al. 1995; Fuks et al. 2003; Lynch et al. 2004; Gillard et al. 2006) and has further been shown to directly inhibit synaptic activity and neurotransmission by inhibiting presynaptic neurotransmitter release (Yang et al., 2007).

The term “prodrug” is art-recognized and is intended to encompass compounds or agents which, under physiological conditions, are converted into a SV2A inhibitor. A common method for making a prodrug is to select moieties which are hydrolyzed or metabolized under physiological conditions to provide the desired compound or agent. In other embodiments, the prodrug is converted by an enzymatic activity of the host animal to an inhibitor of SV2A.

“Analog” is used herein to refer to a compound which functionally resembles another chemical entity, but does not share the identical chemical structure. For example, an analog is sufficiently similar to a base or parent compound such that it can substitute for the base compound in therapeutic applications, despite minor structural differences. i.e., be a SV2A inhibitor.

“Derivative” is used herein to refer to the chemical modification of a compound. Chemical modifications of a compound can include, for example, replacement of hydrogen by an alkyl, acyl, or amino group. Many other modifications are also possible. A derivative of a SV2A inhibitor as used in the methods and compositions of this invention binds SV2A and reduces synaptic function by reducing pre-synaptic vesicle release, i.e., be a SV2A inhibitor.

“Pharmaceutically acceptable salts” is used herein to refer to an agent or a compound according to the invention that is a therapeutically active, non-toxic base and acid salt form of the compounds. The acid addition salt form of a compound that occurs in its free form as a base can be obtained by treating said free base form with an appropriate acid such as an inorganic acid, for example, a hydrohalic such as hydrochloric or hydrobromic, sulfuric, nitric, phosphoric and the like; or an organic acid, such as, for example, acetic, hydroxyacetic, propanoic, lactic, pyruvic, malonic, succinic, maleic, fumaric, malic, tartaric, citric, methanesulfonic, ethanesulfonic, benzenesulfonic, p-toluenesulfonic, cyclic, salicylic, p-aminosalicylic, pamoic and the like. See, e.g., WO 01/062726.

Compounds containing acidic protons may be converted into their therapeutically active, non-toxic base addition salt form, e.g. metal or amine salts, by treatment with appropriate organic and inorganic bases. Appropriate base salt forms include, for example, ammonium salts, alkali and earth alkaline metal salts, e.g. lithium, sodium, potassium, magnesium, calcium salts and the like, salts with organic bases, e.g. N-methyl-D-glucamine, hydrabamine salts, and salts with amino acids such as, for example, arginine, lysine and the like. Conversely, said salt forms can be converted into the free forms by treatment with an appropriate base or acid. Compounds and their salts can be in the form of a solvate, which is included within the scope of the present invention. Such solvates include for example hydrates, alcoholates and the like. See, e.g., WO 01/062726.

Many of the compounds useful in the methods and compositions of this invention have at least one stereogenic center in their structure. This stereogenic center may be present in a R or a S configuration, said R and S notation is used in correspondence with the rules described in Pure Appl. Chem. (1976), 45, 11-30. The invention also relates to all stereoisomeric forms such as enantiomeric and diastereoisomeric forms of the compounds or mixtures thereof (including all possible mixtures of stereoisomers). See, e.g., WO 01/062726.

Furthermore, certain compounds which contain alkenyl groups may exist as Z (zusammen) or E (entgegen) isomers. In each instance, the invention includes both mixture and separate individual isomers. Multiple substituents on the piperidinyl or the azepanyl ring can also stand in either cis or trans relationship to each other with respect to the plane of the piperidinyl or the azepanyl ring. Some of the compounds may also exist in tautomeric forms. Such forms although not explicitly indicated in the above formula are intended to be included within the scope of the present invention. With respect to the methods and compositions of the present invention reference to a compound or compounds is intended to encompass that compound in each of its possible isomeric forms and mixtures thereof unless the particular isomeric form is referred to specifically. See, e.g., WO 01/062726.

This invention provides methods and compositions for treating age-related cognitive impairment or the risk thereof using an inhibitor of SV2A and analogs, derivatives, and pharmaceutically acceptable salts and solvates thereof. The methods and compositions may be used for human patients in clinical applications in the treating age-related cognitive impairment in conditions such as MCI, ARCD and AAMI or for the risk thereof. The dose of the composition and dosage interval for the method is, as described herein, one that is safe and efficacious in those applications.

In certain embodiments of the invention, the inhibitor of SV2A activity is levetiracetam or a pharmaceutically acceptable salt or solvate thereof or a composition containing such levetiracetam, and the invention relates to such levetiracetam or to a levetiracetam-containing compositions and a method of using such levetiracetam or that composition for improving cognitive function in patients suffering from age-related cognitive impairment or at risk thereof, the method comprising the step of administering to the subject a therapeutically effective amount of levetiracetam or a composition containing it. In other embodiments, analogs or derivatives of levetiracetam and pharmaceutically acceptable salt or solvate thereof are used.

In certain embodiments of the invention, the inhibitor of SV2A activity is brivaracetam or a pharmaceutically acceptable salt or solvate thereof or a composition containing such brivaracetam, and the invention relates to such brivaracetam or to a brivaracetam-containing compositions and a method of using such brivaracetam or that composition for improving cognitive function in patients suffering from age-related cognitive impairment or at risk thereof, the method comprising the step of administering to the subject a therapeutically effective amount of brivaracetam or a composition containing it. In other embodiments, analogs or derivatives of brivaracetam and pharmaceutically acceptable salt or solvate thereof are used.

The subject to be treated by the methods and compositions of this invention exhibits age-related cognitive impairment or is at risk of such impairment. In some embodiments, the age-related cognitive impairment includes, without limitation, MCI, ARCD and AAMI.

It will be appreciated that compounds and agents used in the compositions and methods of the present invention preferably should readily penetrate the blood-brain barrier when peripherally administered. Compounds which cannot penetrate the blood-brain barrier, however, can still be effectively administered directly into the central nervous system, e.g., by an intraventricular route.

In some embodiments of this invention, the SV2A inhibitor is formulated with a pharmaceutically acceptable carrier. In other embodiments, no carrier is used. For example, the SV2A inhibitor can be administered alone or as a component of a pharmaceutical formulation (therapeutic composition). The SV2A inhibitor may be formulated for administration in any convenient way for use in human medicine.

In some embodiments, the therapeutic methods of the invention include administering the composition of a compound or agent topically, systemically, or locally. For example, therapeutic compositions of compounds or agents of the invention may be formulated for administration by, for example, injection (e.g., intravenously, subcutaneously, or intramuscularly), inhalation or insufflation (either through the mouth or the nose) or oral, buccal, sublingual, transdermal, nasal, or parenteral administration. The compositions of compounds or agents described herein may be formulated as part of an implant or device, or formulated for slow or extended release. When administered, the therapeutic composition of compounds or agents for use in this invention is in a pyrogen-free, physiologically acceptable form. Techniques and formulations generally may be found in Remington's Pharmaceutical Sciences, Meade Publishing Co., Easton, Pa.

In certain embodiments, pharmaceutical compositions suitable for parenteral administration may comprise the SV2A inhibitor in combination with one or more pharmaceutically acceptable sterile isotonic aqueous or non-aqueous solutions, dispersions, suspensions or emulsions, or sterile powders which may be reconstituted into sterile injectable solutions or dispersions just prior to use, which may contain antioxidants, buffers, bacteriostats, solutes which render the formulation isotonic with the blood of the intended recipient or suspending or thickening agents. Examples of suitable aqueous and non-aqueous carriers which may be employed in the pharmaceutical compositions of the invention include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

A composition comprising a SV2A inhibitor may also contain adjuvants, such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms may be ensured by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the compositions. In addition, prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents which delay absorption, such as aluminum monostearate and gelatin.

In certain embodiments of the invention, compositions comprising a SV2A inhibitor can be administered orally, e.g., in the form of capsules, cachets, pills, tablets, lozenges (using a flavored basis, usually sucrose and acacia or tragacanth), powders, granules, or as a solution or a suspension in an aqueous or non-aqueous liquid, or as an oil-in-water or water-in-oil liquid emulsion, or as an elixir or syrup, or as pastilles (using an inert base, such as gelatin and glycerin, or sucrose and acacia) and the like, each containing a predetermined amount of the SV2A inhibitor as an active ingredient.

In solid dosage forms for oral administration (capsules, tablets, pills, dragees, powders, granules, and the like), one or more compositions comprising the SV2A inhibitor may be mixed with one or more pharmaceutically acceptable carriers, such as sodium citrate or dicalcium phosphate, and/or any of the following: (1) fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and/or silicic acid; (2) binders, such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose, and/or acacia; (3) humectants, such as glycerol; (4) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate; (5) solution retarding agents, such as paraffin; (6) absorption accelerators, such as quaternary ammonium compounds; (7) wetting agents, such as, for example, cetyl alcohol and glycerol monostearate; (8) absorbents, such as kaolin and bentonite clay; (9) lubricants, such a talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof; and (10) coloring agents. In the case of capsules, tablets and pills, the pharmaceutical compositions may also comprise buffering agents. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugars, as well as high molecular weight polyethylene glycols and the like.

As described above, the compounds, agents, and compositions thereof may be administered for slow, controlled or extended release. The term “extended release” is widely recognized in the art of pharmaceutical sciences and is used herein to refer to a controlled release of an active compound or agent from a dosage form to an environment over (throughout or during) an extended period of time, e.g. greater than or equal to one hour. An extended release dosage form will release drug at substantially constant rate over an extended period of time or a substantially constant amount of drug will be released incrementally over an extended period of time. The term “extended release” used herein includes the terms “controlled release”, “prolonged release”, “sustained release”, or “slow release”, as these terms are used in the pharmaceutical sciences. In some embodiments, the extended release dosage is administered in the form of a patch or a pump.

A person of ordinary skill in the art, such as a physician, is readily able to determine the required amount of SV2A inhibitor(s) to treat the subject using the compositions and methods of this invention. It is understood that the dosage regimen will be determined for an individual, taking into consideration, for example, various factors that modify the action of inhibitors of SV2A, the severity or stage of the disease, route of administration, and characteristics unique to the individual, such as age, weight, size, and extent of cognitive impairment.

Furthermore, although the invention has been exemplified using levetiracetam, the results and the method of the instant invention are also applicable to other SV2A inhibitors. Therefore, the present invention also provides compositions of and methods for using other such SV2A inhibitors to improve cognitive function in patients suffering from age-related cognitive impairment or at risk thereof.

It is well-known in the art that normalization to body surface area is an appropriate method for extrapolating doses between species. To calculate the human equivalent dose (HED) from a dosage used in the treatment of age-dependent cognitive impairment in rats, the formula HED (mg/kg)=rat dose (mg/kg)×0.16 may be employed (see Estimating the Safe Starting Dose in Clinical Trials for Therapeutics in Adult Healthy Volunteers, December 2002, Center for Biologics Evaluation and Research). For example, using that formula, a dosage of 10 mg/kg in rats is equivalent to 1.6 mg/kg in humans. This conversion is based on a more general formula HED=animal dose in mg/kg×(animal weight in kg/human weight in kg)0.33.

In certain embodiments of the invention, the dose of the SV2A inhibitor is 0.1 to 5 mg/kg/day (which, given a typical human subject of 70 kg, is 7 to 350 mg/day). Doses that may be used include, but are not limited to 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5 mg/kg/day. In a embodiments, the dose is 1-2 mg/kg/day (which, given a typical human subject of 70 kg, is 70-140 mg/day). In other embodiments of the invention, the dose of the SV2A inhibitor is 0.1 to 0.2 mg/kg/day. Other doses higher than, intermediate to, or less than these doses may also be used and may be determined by one skilled in the art following the methods of this invention.

In certain embodiments of the invention, the dose of the SV2A inhibitor is 0.01 to 2.5 mg/kg/day (which, given a typical human subject of 70 kg, is about 0.7-180 mg/day). Doses that may be used include, but are not limited to 0.01, 0.02, 0.03, 0.04, 0.06, 0.08, 0.12, 0.14, 0.16, 0.18, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.5 mg/kg/day. In some embodiments, the dose is 0.1-2.5 mg/kg/day (which, given a typical human subject of 70 kg, is about 7-180 mg/day). In some embodiments, the dose is 0.4-2.5 mg/kg/day (which, given a typical human subject of 70 kg, is about 25-180 mg/day). In some embodiments of the invention, the dose of the SV2A inhibitor is 0.6 to 1.8 mg/kg/day. In some embodiments of the invention, the dose of the SV2A inhibitor is 0.04 to 2.5 mg/kg/day. In some embodiments of the invention, the dose of the SV2A inhibitor is 0.06 to 1.8 mg/kg/day. Other doses higher than, intermediate to, or less than these doses may also be used and may be determined by one skilled in the art following the methods of this invention.

In certain embodiments of the invention, the interval of administration is 12 or 24 hours. Administration at less frequent intervals, such as once every 6 hours, may also be used. In some embodiments, the SV2A inhibitor is administered every 12 or 24 hours at a total daily dose of 0.1 to 5 mg/kg (e.g., in the case of administration every 12 hours of a daily dose of 2 mg/kg, each administration is 1 mg/kg). In some embodiments, the SV2A inhibitor is administered every 24 hours at a daily dose of 1 to 2 mg/kg. In another embodiment, the selective inhibitor of SV2A is administered every 24 hours at a daily dose of 0.1-0.2 mg/kg. In some embodiments, the SV2A inhibitor is administered every 12 or 24 hours at a daily dose of 0.01 to 2.5 mg/kg (e.g., in the case of administration every 12 hours of a daily dose of 0.8 mg/kg, each administration is 0.4 mg/kg). In some embodiments, the SV2A inhibitor is administered every 12 or 24 hours at a daily dose of 0.1 to 2.5 mg/kg. In some embodiments, the SV2A inhibitor is administered every 12 or 24 hours at a daily dose of 0.4 to 2.5 mg/kg. In some embodiments, the SV2A inhibitor is administered every 12 or 24 hours at a daily dose of 0.6 to 1.8 mg/kg. In some embodiments, the selective inhibitor of SV2A is administered every 12 or 24 hours at a daily dose of 0.04-2.5 mg/kg. In some embodiments, the selective inhibitor of SV2A is administered every 12 or 24 hours at a daily dose of 0.06-1.8 mg/kg.

If administered by an implant, a device or a slow or extended release formulation, the SV2A inhibitor can be administered one time, or one or more times periodically throughout the lifetime of the patient as necessary. Other administration intervals intermediate to or shorter than these dosage intervals for clinical applications may also be used and may be determined by one skilled in the art following the methods of this invention.

Desired time of administration can be determined by routine experimentation by one skilled in the art. For example, the SV2a inhibitor may be administered for a period of 1-4 weeks, 1-3 months, 3-6 months, 6-12 months, 1-2 years, or more, up to the lifetime of the patient.

In addition to inhibitors of SV2A, the compositions and methods of this invention can also include other therapeutically useful agents. These other therapeutically useful agents may be administered in a single formulation, simultaneously or sequentially with the SV2A inhibitors according to the methods of the invention.

In some embodiments, the present invention provides methods and compositions of treating age-related cognitive impairment, which method comprises administering to a subject in need or at risk thereof an inhibitor of SV2A, as described above, in combination with valproic acid (or salts, or solvates, or analogs or derivatives thereof).

Analogs and derivatives of valproic acid (VPA) useful for the methods and compositions of this invention include compounds of the formula:

provided that R may be unsubstituted or substituted by one or more —OH, C1-10 alkoxy, —N(R1)2, —SH, —S—C1-10 alkyl, or aryl. Methods for making the compounds of formula may be found in, for example, U.S. Pat. Nos. 4,558,070; 4,595,695; 4,654,370; 4,895,873; 4,913,906; 5,017,613; 5,019,398; 5,049,586; 5,162,573; 5,440,023; 5,856,569; 6,131,106 and 6,610,326.

VPA refers to 2-propylpentanoate, an anticonvulsant drug that is reported to modify excitatory-inhibitory functions by increasing glutamate reuptake and γ-aminobutyric acid (GABA) concentrations (Hassel et al., 2001; Loscher, 1999; Owens and Nemeroff, 2003). Other names and descriptions of VPA are also envisioned herein, such as Depakote, Valrelease, valproate and sodium valproate. In addition to epilepsy, VPA has been prescribed for treatment of bipolar disorder, migraine, and post-traumatic stress disorder.

In addition to the indications above, valproate is reported to be effective in treating age-related cognitive impairment (Koh et al., 36th annual meeting of the Society for Neuroscience, Oct. 15, 2006, No. 273.14, D.3). Chronic subcutaneous administration to memory-impaired aged rats of 100 mg/kg/day sodium valproate treated their age-related cognitive impairment and their performance in a memory test was significantly improved. This dosage results in a blood total valproate level of 10 μg/ml plasma (10 μg/ml total VPA). Treatment with chronic subcutaneous administration of 50 mg/kg/day VPA, however, was not effective.

In certain embodiments, wherein a SV2A inhibitor is administered in combination with VPA or analogs or derivatives or pharmaceutically acceptable salts or solvates thereof, the dosage of both VPA or analogs or derivatives or pharmaceutically acceptable salts or solvates thereof and the SV2A inhibitor are each sub-therapeutic with respect to treating age-related cognitive impairment when administered alone. In certain embodiments, the daily dose of the SV2A inhibitor, when administered in combination with VPA or analogs or derivatives or pharmaceutically acceptable salts or solvates thereof, is 0.01 to 1 mg/kg. In certain embodiments, the daily dose of the SV2A inhibitor, when administered in combination with VPA or analogs or derivatives or pharmaceutically acceptable salts or solvates thereof, is 0.001 to 1.0 mg/kg. In certain embodiments, the dose of valproate when administered in combination with an SV2A inhibitor is 0.5 to 5 μg/ml total VPA. The doses useful for analogs or derivatives of VPA, or pharmaceutically acceptable salts or solvates thereof are readily determined by those skilled in the art, using the methods of this invention.

It will be understood by one of ordinary skill in the art that the compositions and methods described herein may be adapted and modified as is appropriate for the application being addressed and that the compositions and methods described herein may be employed in other suitable applications, and that such other additions and modifications will not depart from the scope hereof.

This invention will be better understood from the Experimental Details which follow. However, one skilled in the art will readily appreciate that the specific methods and results discussed are merely illustrative of the invention as described more fully in the embodiments which follow thereafter.

EXAMPLESIntroduction and Models of Age-Related Cognitive Impairment

A variety of conditions characterized by cognitive impairment (e.g., Age-Associated Memory Impairment [AAMI], Mild Cognitive Impairment [MCI] and Age-related Cognitive Decline [ARCD]) are believed to be related to aging. Animal models serve as an important resource for developing and evaluating treatments for such age-related cognitive impairments. Features that characterize age-related cognitive impairment in animal models typically extend to age-related cognitive impairment in humans. Efficacy in such animal models is, thus, predictive of efficacy in humans.

Of available models, a Long-Evans rat model of cognitive impairment is particularly well suited for distinguishing the difference between cognitive impairment related to illness and that related to aging. Indeed, extensive behavioral characterization has identified a naturally occurring form of cognitive impairment in an outbred strain of aged Long-Evans rats (Charles River Laboratories; Gallagher et al., Behav. Neurosci. 107:618-626, (1993)). In a behavioral assessment with the Morris Water Maze (MWM), rats learn and remember the location of an escape platform guided by a configuration of spatial cues surrounding the maze. The cognitive basis of performance is tested in probe trials using measures of the animal's spatial bias in searching for the location of the escape platform. Aged rats in the study population have no difficulty swimming to a visible platform, but an age-dependent impairment is detected when the platform is camouflaged, requiring the use of spatial information. Performance for individual aged rats in the outbred Long-Evans strain varies greatly. For example, a proportion of those rats perform on a par with young adults. However, approximately 40-50% fall outside the range of young performance. This variability among aged rats reflects reliable individual differences. Thus, within the aged population some animals are cognitively impaired and designated aged-impaired (AI) and other animals are not impaired and are designated aged-unimpaired (AU). See, e.g., Colombo et al., Proc. Natl. Acad. Sci. 94: 14195-14199, (1997); Gallagher and Burwell, Neurobiol. Aging 10: 691-708, (1989); Rapp and Gallagher, Proc. Natl. Acad. Sci. 93: 9926-9930, (1996); Nicolle et al., Neuroscience 74: 741-756, (1996); and Nicolle et al., J. Neurosci. 19: 9604-9610, (1999).

We have used this rat model to identify genes implicated in age-related changes in cognitive function.

The MWM apparatus consists of a large, circular pool (diameter 1.83 m; height, 0.58 m) filled with water (27° C.) that is made opaque through the addition of non-toxic pigment or some other substance. In the typical “hidden platform” version of the test, rats are trained to find a camouflaged white escape platform (height, 34.5 cm) that is positioned in the center of one quadrant of the maze about 1.0 cm below the water surface. This platform can be retracted to the bottom of the tank or raised to its normal position from outside the maze during behavioral testing. The location of the platform remains constant from trial to trial. Because there are no local cues that mark the position of the platform, the rat's ability to locate it efficiently from any starting position at the perimeter of the pool depends on using information surrounding the maze. The maze is surrounded by black curtains to which white patterns are affixed to provide a configuration of spatial cues. A second platform (height 37.5 cm), with its surface painted black is elevated 2 cm above the water surface during cue training to control for factors unrelated to cognition. The behavior of a rat in the pool is recorded by a camera that is suspended 2.5 m above the center of the pool. The camera is connected to a video tracking system (HVS Image Advanced Tracker VP200) and a PC computer running HVS software developed by Richard Baker of HVS Image, Hampton, UK.

The MWM protocol is optimized for sensitivity to the effects of aging on cognition and for measures of reliable individual differences within the aged population of out-bred Long-Evans rats (Gallagher et al. Behav. Neurosci. 107:618-626, (1993)). Rats receive three trials per day for 8 consecutive days, using a 60 sec inter-trial interval. On each training trial, the rat is released into the maze from one of four equally spaced starting positions around the perimeter of the pool. The starting position varies from trial to trial, thus preventing the use of a response strategy (e.g., always turning left from the start location to locate the escape platform). If a rat does not locate the escape platform within 90 sec on any trial, the experimenter guides the rat to the platform, where it remains for 30 sec. Every sixth trial consists of a probe trial to assess the development of spatial bias in the maze. During these trials, the rat swims with the platform retracted to the bottom of the pool for 30 sec, at which time the platform is raised to its normal position for completion of the escape trial. At the completion of the protocol using the hidden platform, rats are assessed for cue learning using the visible platform. The location of this platform varies from trial to trial in a single session of 6 training trials.

The proximity of the animal's position with respect to the goal is used to analyze the training trial and probe trial performance. The proximity measure is obtained by sampling the position of the animal in the maze (10 times/sec) to provide a record of distance from the escape platform in 1 sec averages. For both probe trials and training trials, a correction procedure is implemented so that trial performance is relatively unbiased by differences in distance to the goal from the various start locations at the perimeter of the pool. In making this correction, the average swimming speed is calculated for each trial (path length/latency). Then, the amount of time required to swim to the goal at that speed from the start location used for the trial is removed from the record prior to computing trial performance, i.e., cumulative distance on training trials and average distance from the goal on probe trials. Thus, scores obtained using the proximity measure are designed to reflect search error, representing deviations from an optimal search, i.e. direct path to the goal and search in the immediate vicinity of that location during probe trials.

Computer records of video-tracking are compiled to provide data on each rat's performance in the maze. Measures on training trials and probe trials are analyzed by Analysis of Variance (ANOVA).

In one set of trials, the performance during training with the hidden, camouflaged platform differs between the groups of young and aged rats [F (1, 23)=12.69, p<0.002]. In this set of trials, no difference between the groups is observed for the cue training trials with a visible platform. In this set of trials, latencies to escape during cue training averaged 9.36 seconds for young and 10.60 seconds for the aged rats.

An average proximity measure on interpolated probe trials is used to calculate a spatial learning index for each individual subject as described in detail in Gallagher et al., Behav. Neurosci. 107:618-26, (1993). When a rat rapidly learns to search for the platform close to its position, its spatial learning index is low. Overall, in one set of trials aged rats differed from young rats [F (1, 23)=15.18, p<0.001]. Aged rats are classified as either unimpaired or impaired relative to the learning index profile of the young study population. Aged rats that fall within the normative range of young rats (index scores <241) are designated aged-unimpaired (AU). The remaining aged subjects that have index scores outside the range of young performance are designated aged-impaired (AI).

Preparation of RNA from Behaviorally Characterized Rats

Twenty-four outbred Long-Evans rats, behaviorally characterized as is described above, are killed by live decapitation to obtain fresh brain tissue. The brain is removed, and the dentate gyms hippocampal region is microdissected from 500 micron sections taken through the transverse axis of the entire hippocampal formation (both left and right hippocampi) of 24 characterized rats. There are 8 animals in each group (AI, AU, and Y).

Total RNA is isolated using Trizol reagent (Invitrogen, Carlsbad, Calif.) according to the standard protocol (homogenization in Trizol reagent followed by chloroform extraction and isopropanol precipitation). Total RNA is further purified using the RNeasy mini kit (Qiagen, Valencia, Calif.). cRNA probes are then generated from the RNA samples at the Johns Hopkins Microarray Core Facility, generally according to Affymetrix specifications.

Briefly, 5 μg of total RNA is used to synthesize first strand cDNA using oligonucleotide probes with 24 oligo-dT plus T7 promoter as primer (Proligo LLC, Boulder, Calif.), and the SuperScript Choice System (Invitrogen). Following the double stranded cDNA synthesis, the product is purified by phenol-chloroform extraction, and biotinilated anti-sense cRNA is generated through in vitro transcription using the BioArray RNA High Yield Transcript Labeling kit (ENZO Life Sciences Inc., Farmingdale, N.Y.). 15 μg of the biotinilated cRNA is fragmented at 94° C. for 35 min (100 mM Trix-acetate, pH 8.2, 500 mM KOAC, 150 mM MgOAC). 10 μg of total fragmented cRNA is hybridized to the RAT genome 230-2 Affymetrix GeneChip array for 16 hours at 45° C. with constant rotation (60 rpm).

Affymetrix Fluidics Station 450 is then used to wash and stain the chips, removing the non-hybridized target and incubating with a streptavidin-phycoerythrin conjugate to stain the biotinilated cRNA. The staining is then amplified using goat immunoglobulin-G (IgG) as blocking reagent and biotinilated anti-streptavidin antibody (goat), followed by a second staining step with a streptavidin-phycoerythrin conjugate.

For quality control of the total RNA from the samples, the Agilent Bioanalyzer, Lab on a Chip technology, is used to confirm that all the samples had optimal rRNA ratios (1:2, for 18S and 28S, respectively) and clean run patterns.

For quality control of the hybridization, chip image, and comparison between chips, the following parameters are considered: Scaling factor: related to the overall intensity of the chip, to confirm the similar signal intensity and staining through out the samples; Background: estimation of unspecific or cross-hybridization; Percentage of present calls: percentage of transcripts that are considered significantly hybridized to the chip (present) by the algorithm; Glyseraldehyde-3-phosphate dehydrogenase (GAPDH) (3′/5′): representation of the RNA integrity by measuring the ratio of 3′ to 5′ regions for the housekeeping gene GAPDH, its presence in the chip and a ratio close to 1 advocates for a good integrity of the target (sample); Spikes (BioB/BioC) to confirm the detection level and sensitivity after hybridization.

Data Analysis of Microarray

Fluorescence is detected using the Affymetrix G3000 GeneArray Scanner and image analysis of each GeneChip is done through the GeneChip Operating System 1.1.1 (GCOS) software from Affymetrix, using the standard default settings. All of the GeneChip arrays use short oligonucleotides for genes in an RNA sample.

For comparison between different chips, global scaling is used, scaling all probe sets to target intensity (TGT) of 150. Total number of present calls and scaling factors are similar across all chips. Further analysis for presence/absence and statistical difference is performed on a region by region basis in the following manner. Probe sets are determined to be present in a region if it had a present call in four of eight animals in a single group.

Probe sets are annotated using the Affymetrix annotation of Jun. 20, 2005, and all probe sets representing a specific gene are identified.

An ANOVA is conducted on the probe set signal values for all present probe sets by combining two groups of animals and comparing them to the third group. An “AI ANOVA” is performed, where AU group are combined with Young group and compared to AI group.

Pearsons's correlations comparing probe set signal values to learning indices were calculated for the aged animals (excluding young) across all present probe sets. As shown in FIG. 1, expression of genes encoding SV2A was significantly increased in aged-impaired (AI) individuals relative to young individuals (Y) and aged-unimpaired individuals (AU) in a set of experiments performed as above. These results show that increased SV2A expression was correlated to the development of age-related cognitive impairment.

Example 2Effect of Levetiracetam in Aged-Impaired RatsMorris Water Maze Results

Six Age-Impaired (AI) Long-Evans rats (as characterized above) were tested for their memory of new spatial information in the MWM, under different drug/control treatment conditions (vehicle control and two different dosage levels of levetiracetam). The MWM protocol was substantially the same as the one described in Example 1. Specifically for this study, a retention trial was performed after the training trials, as described below.

AI rats were given six training trials per training day with a 60-sec inter-trial interval between each training trial for two consecutive days. On each training trial, the rat was released in the maze from one of four equally spaced starting positions around the perimeter of the pool. If the rat did not locate the escape platform within 90 sec on any trial, the experimenter guided the rat to the platform, where it remained for 30 sec. 30 minutes to 1 hour prior to all the training trials on each training day, AI rats were pretreated with one of three drug conditions: 1) vehicle control (0.9% saline solution); 2) levetiracetam (5 m/kg/day); and 3) levetiracetam (10 mg/kg/day); through intraperitoneal (i.p.) injection. The same six AI rats were used for the entire trials so that each treatment condition was tested on all six rats. Therefore, to counterbalance any potential bias, both the location of the escape platform and the spatial cues surrounding the water maze were different in the three treatment conditions. Therefore, using one set of locations and spatial cues, two rats were treated with saline control solution, two with levetiracetam (5 m/kg/day) and two with levetiracetam (10 mg/kg/day). Using the second set of locations and spatial cues, the two rats treated with saline control solution in the first test were treated with either levetiracetam (5 m/kg/day) or levetiracetam (10 mg/kg/day), and the two rats previously treated with levetiracetam (5 m/kg/day) were treated with either saline control solution or levetiracetam (10 mg/kg/day), and the two rats previously treated with levetiracetam (10 mg/kg/day) were treated with either saline control solution or levetiracetam (5 m/kg/day). Using the last set of locations and spatial cues, the rat groupings were again switched so that each group was treated with a different condition than they had been treated previously.

After the second training day and completion of the twelve training trials (over the two days), the rat was returned to its home cage and placed in the animal housing room. After a delay of 24 hours from the last training trial, the rat was given one testing trial (the “retention trial”), which was the same MWM task as the training trials, but with the escape platform removed.

For the retention trial, the MWM circular pool was divided into 4 quadrants. The particular quadrant where the escape platform was placed in the training trials is referred as “target quadrant”. The particular region where the platform was located in the training trials is referred as “target annulus”. In the retention trial, the time the AI rats spent swimming in the target quadrant is measured and further plotted as a percentage of total swimming time. FIG. 2 displays the results of one such set of retention trials. The time the AI rats spend in the target annulus is also measured. FIG. 2 displays the results of one such set of retention trials. Time data are collected for all three drug treatment conditions.

In the retention trial, whose results are depicted in FIG. 2, the time the AI rats spent in the target quadrant was approximately 25%, which is a performance equivalent to them having no memory of the platfrom location. This performance did not significantly improve in the group treated with levetiractam at 5 mg/kg/day. However, the group treated with levetiractam at 10 mg/kg/day demonstrated significantly improved memory as compared to vehicle-treated controls, as indicated by a significant increase in the time spent in the target quadrant to approximately 35% of total swimming time (see FIG. 2). That level of performance is equivalent to young and age-unimpaired rats, indicating that treatment with 10 mg/kg/day levetiractam resulted in a significant recovery of the AI rats' ability to navigate this MWM. The effectivness of the 10 mg/kg/day levetiracetam treatment was also seen in the time spent in the target annulus (see FIG. 2).

Radial Arm Maze Results

The effects of levetiracetam on the spatial memory retention of aged-impaired (AI) rats were assessed in a Radial Arm Maze (RAM) behavioral task using vehicle control and five different dosage levels of levetiracetam (1.25 mg/kg/day, 2.5 mg/kg/day, 5 mg/kg/day, 10 mg/kg/day and 20 mg/kg/day). RAM behavioral tasks were preformed on ten AI rats. All six treatment conditions were tested on all ten rats, as described above for the MWM test.

The RAM apparatus used consisted of eight equidistantly-spaced arms. An elevated maze arm (7 cm width×75 cm length) projected from each facet of an octagonal center platform (30 cm diameter, 51.5 cm height). Clear side walls on the arms were 10 cm high and were angled at 65° to form a trough. A food well (4 cm diameter, 2 cm deep) was located at the distal end of each arm. Froot Loops™ (Kellogg Company) were used as rewards. Blocks constructed of Plexiglas™ (30 cm height×12 cm width) could be positioned to prevent entry to any arm. Numerous extra maze cues surrounding the apparatus were also provided.

The AI rats were initially subjected to a pre-training test (Chappell et al. Neuropharmacology 37: 481-487, 1998). The pre-training test consisted of a habituation phase (4 days), a training phase on the standard win-shift task (18 days) and another training phase (14 days) in which a brief delay was imposed between presentation of a subset of arms designated by the experimenter (e.g., 5 arms available and 3 arms blocked) and completion of the eight-arm win-shift task (i.e., with all eight arms available).

In the habituation phase, rats were familiarized to the maze for an 8-minute session on four consecutive days. In each of these sessions food rewards were scattered on the RAM, initially on the center platform and arms and then progressively confined to the arms. After this habituation phase, a standard training protocol was used, in which a food pellet was located at the end of each arm. Rats received one trial each day for 18 days. Each daily trial terminated when all eight food pellets had been obtained or when either 16 choices were made or 15 minutes had elapsed. After completion of this training phase, a second training phase was carried out in which the memory demand was increased by imposing a brief delay during the trial. At the beginning of each trial, three arms of the eight-arm maze were blocked. Rats were allowed to obtain food on the five arms to which access was permitted during this initial ‘information phase’ of the trial. Rats were then removed from the maze for 60 seconds, during which time the barriers on the maze were removed, thus allowing access to all eight arms. Rats were then placed back onto the center platform and allowed to obtain the remaining food rewards during this ‘retention test’ phase of the trial. The identity and configuration of the blocked arms varied across trials.

The number of “errors” the AI rats made during the retention test phase was tracked. An error occurred in the trial if the rats entered an arm from which food had already been retrieved in the pre-delay component of the trial, or if it re-visited an arm in the post-delay session that had already been visited.

After completion of the pre-training test, rats were subjected to trials with more extended delay intervals, i.e., a one-hour delay, between the information phase (presentation with some blocked arms) and the retention test (presentation of all arms). During the delay interval, rats remained off to the side of the maze in the testing room, on carts in their individual home cages. AI rats were pretreated 30-40 minutes before daily trials with a one-time shot of the following six conditions: 1) vehicle control (0.9% saline solution); 2) levetiracetam (1.25 mg/kg/day); 3) levetiracetam (2.5 mg/kg/day); 4) levetiracetam (5 mg/kg/day); 5) levetiracetam (10 mg/kg/day); 6) levetiracetam (20 mg/kg/day); through intraperitoneal (i.p.) injection. Injections were given every other day with intervening washout days. Each AI rat was treated with all six conditions within 23 days of testing. To counterbalance any potential bias, drug effect was assessed using ascending-descending dose series, i.e., the dose series was given first in an ascending order and then repeated in a descending order. Therefore, each dose had two determinations.

Parametric statistics (paired t-tests) was used to compare the retention test performance of the AI rats in the one-hour delay version of the RAM task in the context of different doses of levetiracetam and vehicle control (see FIG. 3). The average numbers of errors that occurred in the trials were also significantly fewer with levetiracetam treatment of 5 mg/kg/day (average no. of errors±standard error of the mean (SEM)=0.75±0.32) and 10 mg/kg/day (average no. of errors±SEM=0.80±0.27) than using vehicle control (average no. of errors±SEM=2.00±0.42). Relative to vehicle control treatment, levetiracetam significantly improved memory performance at 5 mg/kg/day (t(9)=2.18, p=0.057) and 10 mg/kg/day (t(9)=2.37, p=0.042).

To calculate the human equivalent dose (HED) for levetiracetam dosage for treatment of age-dependent cognitive impairment in humans, we employed the formula HED (mg/kg)=rat dose (mg/kg)×0.16 (see Estimating the Safe Starting Dose in Clinical Trials for Therapeutics in Adult Healthy Volunteers, December 2002, Center for Biologics Evaluation and Research). Therefore, the dosage of 5 mg/kg/day in rats is equivalent to 0.8 mg/kg/day in humans and the dosage of 10 mg/kg/day in rats is equivalent to 1.6 mg/kg/day in humans.

What is claimed is:1. A method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of a synaptic vesicle protein 2A (SV2A) inhibitor or a pharmaceutically acceptable salt thereof.2. The method of claim 1, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is selected from the group of SV2A inhibitors referred to in International Patent Application WO 2001/062726, International Patent Application WO 2002/094787, International Patent Application WO 2004/087658, U.S. Pat. No. 7,244,747, International Patent Application WO 2007/065595, US Patent Application 2008/0081832, International Patent Application WO 2006/128692, International Patent Application WO 2006/128693, UK Patent No. 1,039,113, and UK Patent No. 1,309,692.3. The method of claim 2, wherein the SV2A inhibitor is selected from the group consisting of levetiracetam, seletracetam, and brivaracetam or pharmaceutically acceptable salts thereof.4. The method of claim 3, wherein the SV2A inhibitor is levetiracetam or a pharmaceutically acceptable salt thereof.5. The method of claim 3, wherein the SV2A inhibitor is brivaracetam or a pharmaceutically acceptable salt thereof.6. The method of any one of claims 1 to 5, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of 0.1 mg/kg to 5 mg/kg.7. The method of claim 6, wherein the daily dose is 0.1-0.2 mg/kg.8. The method of any one of claims 1 to 5, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is administered every 12 or 24 hours at a daily dose of 0.01 mg/kg to 2.5 mg/kg.9. The method of claim 8, wherein the daily dose is 0.1-2.5 mg/kg.10. The method of claim 8, wherein the daily dose is 0.4-2.5 mg/kg.11. The method of claim 8, wherein the daily dose is 0.6-1.8 mg/kg.12. The method of claim 8, wherein the daily dose is 0.04-2.5 mg/kg.13. The method of claim 8, wherein the daily dose is 0.06-1.8 mg/kg.14. A method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject an SV2A inhibitor or a pharmaceutically acceptable salt thereof in combination with valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof.15. The method of claim 14, wherein the valproate is administered at a daily dose such that the subject maintains a blood total valproate level of 0.5 to 5 μg/ml plasma, and wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is administered at a daily dose of 0.01 to 1 mg/kg.16. The method of claim 14, wherein the valproate is administered at a daily dose such that the subject maintains a blood total valproate level of 0.5 to 5 μg/ml plasma, and wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is administered at a daily dose of 0.001 to 1 mg/kg.17. The method of any one of claims 14 to 16, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof is selected from the group of SV2A inhibitors referred to in International Patent Application WO 2001/062726, International Patent Application WO 2002/094787, International Patent Application WO 2004/087658, U.S. Pat. No. 7,244,747, International Patent Application WO 2007/065595, US Patent Application 2008/0081832, International Patent Application WO 2006/128692, International Patent Application WO 2006/128693, UK Patent No. 1,039,113, and UK Patent No. 1,309,692.18. The method of any one of claims 14 to 16, wherein the SV2A inhibitor is selected from the group consisting of levetiracetam, seletracetam, and brivaracetam or pharmaceutically acceptable salts thereof.19. The method of claim 18, wherein the SV2A inhibitor is levetiracetam or a pharmaceutically acceptable salt thereof.20. The method of claim 18, wherein the SV2A inhibitor is brivaracetam or a pharmaceutically acceptable salt thereof.21. The method of claim 14, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof and the valproate or a pharmaceutically acceptable salt thereof are administered simultaneously.22. The method of claim 14, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof and the valproate or a pharmaceutically acceptable salt thereof are administered in a single formulation.23. The method of claim 14, wherein the SV2A inhibitor or a pharmaceutically acceptable salt thereof and the valproate or a pharmaceutically acceptable salt thereof are administered sequentially.24. A pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof, the SV2A inhibitor or a pharmaceutically acceptable salt thereof being present in an amount of 5-140 mg.25. A pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof, the SV2A inhibitor or a pharmaceutically acceptable salt thereof being present in an amount of 0.7-180 mg.26. A pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof, the SV2A inhibitor or a pharmaceutically acceptable salt thereof being present in an amount of 3-50 mg, and valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof.27. A pharmaceutical composition for improving cognitive function in a subject with age-related cognitive impairment or at risk thereof, the composition comprising a SV2A inhibitor or a pharmaceutically acceptable salt thereof, the SV2A inhibitor or a pharmaceutically acceptable salt thereof being present in an amount of 0.07-50 mg, and valproate or an analog or a derivative or a pharmaceutically acceptable salt thereof.28. A method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of levetiracetam or a pharmaceutically acceptable salt thereof.29. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 1-2 mg/kg.30. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 70-150 mg.31. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 0.1-2.5 mg/kg.32. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 7-180 mg.33. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 0.4-2.5 mg/kg.34. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 25-180 mg.35. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 0.6-1.8 mg/kg.36. The method of claim 28, wherein the levetiracetam is administered every 12 or 24 hours at a daily dose of 40-130 mg.37. A method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of brivaracetam or a pharmaceutically acceptable salt thereof.38. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 0.1-0.2 mg/kg.39. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 7-15 mg.40. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 0.01-2.5 mg/kg.41. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 0.7-180 mg.42. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 0.04-2.5 mg/kg.43. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 2.5-180 mg.44. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 0.06-1.8 mg/kg.45. The method of claim 37, wherein the brivaracetam is administered every 12 or 24 hours at a daily dose of 4.0-130 mg.46. A method for treating age-related cognitive impairment in a subject in need or at risk thereof, the method comprising the step of administering to said subject a therapeutically effective amount of seletracetam or a pharmaceutically acceptable salt thereof.

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